Bit of advice needed here...
Our 2007 Fiat Bravo, equipped with automatic climate control is suffering from misting up windows in this cold weather. We have had the car since new and have never had problems previously, even in cold snaps. Its at a point now where you need to open the side windows when approaching junctions.
The system is set to full auto and the air con is constantly on which in theory should be de humidifying aswell.
The handbook says that the compressor wont engage at low temps (less than 2C IIRC)
I have taken to an aircon specialist who has re gassed the system (wasnt too bad anyway) and Fiat who changed pollen filter and checked the system.
Still no better.
There is no residual moisture in the carpets etc and the misting goes when parked, so no wet carpets.
Just to confuse matters I have an Alfa GTA with the same system and it doesnt suffer at all from misted windows...
Any ideas? TIA
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Is it set to recirculate?
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2C seems a bit cool for aircon to cut out, it is usually nearer 4 or 5C. Don't take the "instructions" as gospel, it only needs a sensor to be a bit "off" in its calibration.
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I find that the best thing to do is to void the car of warm humid air before leaving it overnight. For the last 5 minutes when driving back to home, set heater to cold, full fan and and open the windows slightly. SWMBO loves it ;)
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in my limited experience of these things, on recirculate or not, aircon dehumidifes the air that passes through it (hence the puddles you see under some parked cars in summer), but it needs to be working before it will do that.
the only peculairity on the (Škoda/VW) system I'm familiar with is that it relies on the coolant being warmed up a bit before the aircon works - I don't know if FIAT systems are like this though.
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I occasionally get this issue in my Honda and find a quick blast on the demist setting clears the windows.
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Mine did this a few weeks ago (before the really cold spell). Booked it in and the only thing they found wrong was damp leaves in the pollen filter. They were removed and it's been fine since even when it was -6 deg C outside.
My Mazda6 also has auto climate control (not air-con) so it's on all the time.
Edit: in response to Redfire above.... putting it to demist the windscreen made the problem worse. The aircon was blowing the moisture on my windscreen.
Last edited by: rtj70 on Tue 14 Dec 10 at 08:51
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Yes on pressing the max demist button it does clear the windscreen and part of the side windows. On travelling to Leeds the other night (from Middlesbrough), I needed to do this every 10 mins or so and was uncomfotably hot
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Its happened to me on virtually every airconned car I have had since 2003. With all of them the problem comes and goes.
I think its due to moisture thats condensed in the pipes overnight. Soon passes.
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>> My Mazda6 also has auto climate control (not air-con) so it's on all the time.
>>
>> worse. The aircon was blowing the moisture on my windscreen.
>>
Make up your mind. Do you have air-con or climate-control? :-)
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>> Is it set to recirculate?
>> No it is on "incoming"!.
But is the flap operating that allows either incoming or recirculates the air?
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Fiat had it yesterday and said it was all operating ok
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>> Fiat had it yesterday and said it was all operating ok
If you're not satisfied, take it to another Fiat franchised dealer.
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PR ~ moisture extracted from the incoming ambient air by the aircon will never drain away completely. If the aircon is turned off or the compressor stops the residual moisture will come into the car when there is airflow through the heater/aircon ducting. It's probably this which is causing your misting problem. I've had this problem in both the cars I've owned which had aircon and my solution is to not use the aircon in winter. Don't just take my word for it ~ you can prove it yourself by not using the aircon for a few days until the residual moisture has dried out.
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>> ... and my solution is to not use the aircon in winter.
Same for me. Had a/c for years and never normally use it in winter.
Also as mentioned above, even when I do us it, I try to remember to turn it off before I get home. One thing I would say is that in some cars with climate control it stays on at a reduced percentage for quite a time after you press the button to turn it off (Mercs and BMWs certainly do that) and I read the other day that on some vehicles it never fully turns off.
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It has been suggested, over on the Dark Side, that one needs to run the a/c for a few minutes every week to keep the pump seals in good order.
Last edited by: Perky Penguin (p) on Tue 14 Dec 10 at 11:55
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>> It has been suggested, over on the Dark Side, that one needs to run the
>> a/c for a few minutes every week to keep the pump seals in good order.
>> If one has it on all the time, and it is not cooling, it is
>> using minimal energy and in my car it seems to dehumidify the air anyway.
>>
If the ambient temperature is below about 4C it won't use any energy because the compressor won't engage and the system will not do anything.
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>> If the ambient temperature is below about 4C it won't use any energy because the
>> compressor won't engage and the system will not do anything.
>>
You'll have just to take your car to L'escargot heated garage.
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>> It has been suggested, over on the Dark Side, that one needs to run the
>> a/c for a few minutes every week to keep the pump seals in good order.
>>
There are lot of old wives' tales spoken about cars. My car's Owners Guide is pretty comprehensive and all it says is to turn it off when it is not required. I think the manufacturer knows best, so I follow their recommendations. My car is 7.5 years old and the aircon has yet to need any attention.
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>>
>> There are lot of old wives' tales spoken about cars. My car's Owners Guide is
>> pretty comprehensive and all it says is to turn it off when it is not
>> required. I think the manufacturer knows best, so I follow their recommendations. My car is
>> 7.5 years old and the aircon has yet to need any attention.
>>
This is certainly common advice which is possibly contained in some manufacturers' recommendations, the logic being that the coolant gas has lubricating properties for the compressor seals which can 'dry out' and fail if the aircon is not operated periodically (IIRC monthly). I've had aircon on cars for the past 15 years and only the aircon on Vauxhalls has failed and then as a result of dealer bungling and other failures, however I run the aircon almost constantly - except in temperatures below 4DegC where there is no point and temperature fluctuations cause the car to steam up as the compressor switches in and out.......
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>> There are lot of old wives' tales spoken about cars. My car's Owners Guide is
>> pretty comprehensive and all it says is to turn it off when it is not
>> required. I think the manufacturer knows best, so I follow their recommendations. My car is 7.5 years old and the aircon has yet to need any attention.
IIRC the Focus automatically put the AC on when you change the airflow to the windscreen, so the AC on your car probably gets a regular workout which is why the seals haven't dried out.
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>> IIRC the Focus automatically put the AC on when you change the airflow to the
>> windscreen, so the AC on your car probably gets a regular workout which is why
>> the seals haven't dried out.
>>
I seem to remember you've said that before.
It doesn't happen on mine, unless I press the appropriate button. The normal airflow to screen is just via the heater. Later ones may be different, but I hope not. I like to be in control of things myself.
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...IIRC the Focus automatically put the AC on when you change the airflow to the windscreen...
Mine does that, and it automatically turns on both heated screens when it's cold, irrespective of ventilation settings.
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>> I like to be in control of things myself.
>>
Daughter's Mitsubishi Colt does this - and hers is a fairly manual setup. Twizzle the airflow knob to point to screen and the a/c comes on. There's no indication the a/c is on, we only realised when the screen got condensation on the outside.
I can't remember driving a car for years where pressing the demist button doesn't operate the a/c too.
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The temperature has been at or around freezing for around 2 weeks here, so no aircon, and it is still happening. I will check all the drain / inlets again though.
Zero - this is the first time in 3 years this has happened, and in 9 years in 3 Alfas with this system I have never had misted windows
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This appears to be a recurring theme and I wonder whether people fail to understand the fundamental limitations of aircon. It's simple, aircon will not (can not) work below about 4DegC.
I see posts with people saying 'I leave it on and it's fine', the fact is that it will not be operating below around 4DegC.
If it has been previously operating (because the ambient temperature was higher) and the temperature drops then you'll mist up because there will be residual moisture around the condenser over which the air still passes. This will be further compounded if you have recirc on since the air will pass over the damp condenser multiple times.
Of course, if you still get the problem when the ambient temperature rises then you have a problem with your aircon !
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Had this a month or two back. Changed the pollen filter. Problem went away.
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>> This appears to be a recurring theme and I wonder whether people fail to understand
>> the fundamental limitations of aircon. It's simple, aircon will not (can not) work below about
>> 4DegC.
>>
>> I see posts with people saying 'I leave it on and it's fine', the fact
>> is that it will not be operating below around 4DegC.
>>
I have lost count of the times I have posted this fact. The words brick wall, head, and bang, come to mind.
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Condensation forms on the outside of the driver's window on the CC3 when the interior demist vent warms the inside of the glass.
Complicated life we lead, isn't it?
I'm just grateful I'm able to store my killer salt a safe distance from the house.
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I have had climate control in the last three carsso that is ten years. I never turned climate off and ther only time to get misting up was recently before the very cold weather. It happened as soon as the car started. Leaves removed from pollen filter and all seems fine now.
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>> Condensation forms on the outside of the driver's window on the CC3 when the interior
>> demist vent warms the inside of the glass.
>>
Classic symptoms of a leaking roof, Iffy :-)
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The air-con must be operating even if only to act as a de-humidifier, as I can see every time I use it in winter when the external air temp is around or below zero. How does this happen if the air-con is not working?
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The compressor spins all the time, regardless of temperature.
Don't know if that's relevant.
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>> The compressor spins all the time, regardless of temperature.
>>
>> Don't know if that's relevant.
Mine dont. Its got an electromagnetic clutch.
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>> Mine don't. Its got an electromagnetic clutch.
>>
As do they all. The pulley is going round, not necessarily the compressor.
Last edited by: Old Navy on Tue 14 Dec 10 at 10:50
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...As do they all...
OK, I'll rephrase that.
The air con cannot be working when the compressor's clutch is engaged, or is it disengaged? - never can remember which is which.
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To be more precise, the chilling/cooling function of the air con is not working.
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Does a car move when its clutch is disengaged? And I can spot a wind up. :-)
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engage = both side spinning
disengage = one side spinning, the other not.
In my estimation anyway.
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..engage = both side spinning...disengage = one side spinning, the other not...
Wiki agrees:
Clutch - Wikipedia, the free encyclopedia
No pressure on the pedal means that the clutch plates are engaged (driving), while pressing the pedal disengages the clutch plates, allowing the driver to ...
Double clutch - Clutch control - Centrifugal clutch - Slipper clutch
en.wikipedia.org/wiki/Clutch - Cached - Similar
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>> The air-con must be operating even if only to act as a de-humidifier, as I
>> can see every time I use it in winter when the external air temp is
>> around or below zero. How does this happen if the air-con is not working?
>>
This breaks the laws of thermodynamics, for the avoidance of doubt, it does not, it can not, it will not, dehumidify below 4DegC.
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>> >> The air-con must be operating even if only to act as a de-humidifier, as
>> I
>> >> can see every time I use it in winter when the external air temp
>> is
>> >> around or below zero. How does this happen if the air-con is not working?
>>
>> >>
>>
>> This breaks the laws of thermodynamics, for the avoidance of doubt, it does not, it
>> can not, it will not, dehumidify below 4DegC.
>>
>>
You are wasting your time and effort, idle_chatterer, some people just don't understand.
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It's not a case of lack of understanding ON. It's simply practical experience of real life events and effects. Anyway, like I've said elsewhere, I'll do what seems to work for me and others can do what they feel comfortable with. You can theorise all you like, in practice I know what works on my cars.
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>> some people just don't understand.
You're right! Some people don't understand why the AC still clears the mist from the windscreen quicker when switched on than when it's off and the temperature outside is less than 4 deg C.
Must be witchcraft. No other explanation for it - but then again, Dave (post further down) is/was an AC engineer and I'll more than happily accept his explanation.
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>> >> This appears to be a recurring theme and I wonder whether people fail to
>> understand
>> >> the fundamental limitations of aircon. It's simple, aircon will not (can not) work below
>> about
>> >> 4DegC.
>> >>
>> >> I see posts with people saying 'I leave it on and it's fine', the
>> fact
>> >> is that it will not be operating below around 4DegC.
>> >>
>>
>> I have lost count of the times I have posted this fact. The words brick
>> wall, head, and bang, come to mind.
>>
This is a motoring forum. You don't expect anyone here to know anything about thermodynamics, do you? :-)
I have only owned cars with climate-control or cars with no air-con. I leave the climate on all the time, temperature set in the range between 21 to 23 depending on on how hot/cold I feel. I have never had the misting problem.
Never had any cars with plain air-con, but did hire one in USA a few years ago in Vegas. That did use to get the misting problem on start-up even in hot Vegas due to the trapped condensate in the system.
Reading the responses to this thread, my conclusion is that some cars are better than others with regard to the efficiency of their heating, cooling, ventilation systems.
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>> This is a motoring forum. You don't expect anyone here to know anything about thermodynamics,
>> do you? :-)
I expect them to have a vague idea how their cars work, If they can read this they can read its instruction manual. :-)
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>> I expect them to have a vague idea how their cars work, If they can
>> read this they can read its instruction manual. :-)
>>
There ought to be a joining test!
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Excellent idea, 100 questions should cover the basics. :-)
As new members would benefit the forum we will probably get the sack for suggesting it.
Last edited by: Old Navy on Tue 14 Dec 10 at 11:36
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NO, Repeat NO questions about spelling, grammar, or literary skills.
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>> NO, Repeat NO questions about spelling, grammar, or literary skills.
>>
Agreed . The current membership would all be expelled...
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...NO, Repeat NO questions about spelling, grammar, or literary skills...
LOTS, repeat LOTS of questions about spelling, grammar, and literary skills.
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>> LOTS, repeat LOTS of questions about spelling, grammar, and literary skills.
>>
Back in your box iffy, its a hypothetical car quiz. :-)
Last edited by: Old Navy on Tue 14 Dec 10 at 11:50
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AIr con not demisting?
When was the panel filter changed? If ever.
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>> I expect them to have a vague idea how their cars work, If they can
>> read this they can read its instruction manual. :-)
>>
First question should be: describe and explain the process by which fuel in your tank ends up providing torque at the wheels.
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Thanks for some of the sarcastic responses ;) I am aware the compressor does not engage at low temps (see original post) what has changed recently is that the car is suffering from misting up windows where it didnt before.
I have not tried turning the air con part of the auto climate off but will try that now..(or when the temps drop again!)
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>> (or when the temps drop again!)
>>
You won't have to, it will do it itself regardless of what you do.
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I meant the outside temp..
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Sorry was a bit slow there ;)
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No problem, I get brain fade, in my case it is due to age. I think. :-)
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The uprated madf model has enlarged thinking capacity which prevents brain fade, incontinence and other afflictions of old age.
madf is 103.
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Even if the outside temperature is in the minus figures, my CC still removes any mist on the inside of the car windows, so the dehumidifying part of it must still work regardless what the outside temperature is. If I turn off the CC then the mist takes longer to clear.
I thought we had this conversation a week or so ago?
Last edited by: VxFan on Tue 14 Dec 10 at 12:26
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...I give up!!!!...
I think it's due to wind chill on the glass.
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ditto with Yaris and Matiz...
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It's possible that the when set to demist the AC engages for a minute or two, regardless of the ambient temp (but see below), to provide some dry air to demist the windows. The cooling and dehumidifying functions are one and the same - the act of cooling the air causes the water to condense out (think taking a drinks can out of the fridge on a warm day!). However, in general it doesn't engage below about 4°C because then the dewpoint is possibly below 0°C, and the condensed water would just freeze on the evaporator. There will be a point where the boiling temp of the refrigerant in the evaporator is below the ambient temp (I'm not sure, but I would expect the temp to be above 0°C so that you don't get ice on the evap in normal operation), and then there is no point in it switching on - heat can't flow 'uphill'.
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>> Even if the outside temperature is in the minus figures, my CC still removes any
>> mist on the inside of the car windows, so the dehumidifying part of it must
>> still work regardless what the outside temperature is. If I turn off the CC then
>> the mist takes longer to clear.
>>
>> I thought we had this conversation a week or so ago?
My air conditioning comes on regardless of outside temperature. If I need to demist it quickly in winter I'll switch the aircon on and keep the temperature around 22 degrees. How do I know the AC is on? The temperature of the air through the vents will go down-where it was previously very warm it goes to lukewarm, so the AC is doing it's job of cooling the air and dehumidifying. Also I can hear the clutch kicking in and out, and the revs change when sitting idling at traffic lights. When I turn the AC off, the temperature becomes much warmer within a short period of time.
Maybe the aircon is not supposed to work below 4 degrees as people claim, but not in my car. Maybe the sensor that controls this has gone kaput as it is a 12 year old car, but I would rather it worked at all times of the year because as mentioned above, I'm one of those people who switches it on for 5-10 minutes each week through the winter to keep the seals from drying out.The aircon has been ice cold and working perfectly since I bought it in 2005, and I intend to keep it working while I own it.
I can't stand sitting in a furnace in a summer traffic jam.
Last edited by: corax on Tue 14 Dec 10 at 17:28
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>> Even if the outside temperature is in the minus figures, my CC still removes any
>> mist on the inside of the car windows, so the dehumidifying part of it must
>> still work regardless what the outside temperature is. If I turn off the CC then
>> the mist takes longer to clear.
Well I've just taken my son to work in his Panda, and that demisted itself this morning even though it was sub zero - so the aircon must be working.
Funny that, it has no aircon.
Of course, the answer might be that the relative humidity falls, even though the moisture content of the air is unchanged, owing to the increase in air temperature ;-)
Last edited by: Manatee on Wed 15 Dec 10 at 07:22
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Our Galaxy has auto c/c permanently set to 21 degrees. In this weather the interior steams up as the warm air from the system hits the large, cold interior and there is a lot of glass for it to settle on. I crack the front windows a bit to regulate the air inside which soon clears it.
My Vectra has manual aircon permanently switched on and I don't get any misting up at this time of year.
I'm inclined to believe the theory that the air is not dehumidified below 4 degrees which would explain the issue with our Galaxy and the OP's FIAT, but what about my Vectra?
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I don't know if the compressor is off or not, but last week with the outside temerature below -2C the climate control on my Accord Tourer very quickly demisted the windows.
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Selecting the windscreen on our Civic brings the aircon light on, even where it was previously deselected. My theory to account for this seeming defiance of the laws of thermodynamics, is that the system switches to full or part recycling. Ambient internal air flowing over the condensor is soon above freezing point. Whatever happens there is a marked contrast in effectiveness with aircon on compared with aircon off. Ergo, the internal air is being dehumidified. The only way that can happen is with the aircon operational. Even at -8C which has been the case locally.
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>> Reading the responses to this thread, my conclusion is that some cars are better than
>> others with regard to the efficiency of their heating, cooling, ventilation systems.
Yes Suppose. My dads Honda Accord had a very poor flow of air through the car only made bearable by having the fan on a relatively high speed. Nothing wrong with the pollen filter.
My BMW has superb heating and ventilation, I can't fault it. Excellent flow of air and the ability to have cold air to the face/warm air to the feet at the same time.
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There's a number of different ways of controlling the a/c function at low temperatures, and a number of different ways in which the compressor operates. Some can be affected by engine bay temperatures, usually the older systems that rely on pressure, and some have electronic control. The newer sytems will also run the compressor even in low temperatures for the demist function, as it's a fairly safe bet that the evaporator won't freeze up as the moisture content is low. Refrigerant R134a has a boiling point of minus 32C, so it's certainly capable of getting cold enough to help demisting.
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>> . Refrigerant R134a has a boiling point of minus 32C, so
>> it's certainly capable of getting cold enough to help demisting.
>>
But the problem is ice formation on the condenser, water still freezes at these low temperatures (I think it's called rime and can happen above 0DegC with super-cooled water/air mixtures such as freezing fog). It's what happens in clouds when hailstones form I think.....
So, running the condenser below 4DegC risks ice build up.
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If external air is shut off, and re-circulation selected (ours does this automaticaly I think), then the condenser is only exposed to a flow of internal air, which is a) somewhat lower initially, b) quickly warmed by the heating system. Probably the demist function runs at part capacity: it's not trying to cool the car internal volume. From experience it does seem that the demist function is active. So there:)
Last edited by: NortonES2 on Wed 15 Dec 10 at 09:16
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>> If external air is shut off, and re-circulation selected (ours does this automaticaly I think),
>> then the condenser is only exposed to a flow of internal air, which is a)
With recirc on and with compressor off, I think in theory your car should mist up - because the moisture content increases through occupant's exhalation and sweating.
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Yes, and the swearing! On the Civic, selecting demist brings the aircon light on: I presumed that action also selects recirculation. If I switch to cabin only, misting recurs.
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>>
>> I have lost count of the times I have posted this fact. The words brick
>> wall, head, and bang, come to mind.
>>
ON, perhaps the Earth really is flat and circled by the Sun because that is what our eyes tell us ? If people want to believe that their aircon is anything other than an ornament (with a pretty light) below 4DegC then that is their right.....
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OK fine, not even going to attempt to argue with the science but will someone please explain why it is then, no matter how cold it is outside, that my car demists itself and keeps itself demisted far more efficiently with the AC on? It just does. Not trying to argue with the "laws of thermodynamics" just reporting what happens in real life.
Is it perhaps the same reason why my diesel car is quite capaple of warming itself up sufficiently at idle to de-frost the windows on a cold day despite that being impossible too?
Perhaps banging heads against brick walls is affecting eyesight because both of these phenomena are plain to see...
:-)
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Try turning the aircon off (after it has been on, and when there is still airflow through it) and then see whether the screen mists up.
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That's the thing, it does. Even if it has been cold for days. Anyway, it's no big deal, I just leave it on all the time and don't get misty windows. Don't have to worry about the physics then !
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I leave my aircon on all the time. When I switch it off, it mists up. It clears much much quicker with aircon switched on. Same in the last car.
Everything what Humph said.
Apart from the diesel bit. What's one of them?
Last edited by: BiggerBadderDave on Wed 15 Dec 10 at 08:28
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>> I leave my aircon on all the time. When I switch it off, it mists
>> up.
It's the residual moisture in the aircon airways coming into the car.
I don't see the point in warming the air up with the heater and then cooling it down with the aircon ~ or the other way round, in whichever sequence it happens. And I'm surprised the tree huggers haven't complained about it being environmentally unfriendly. If I want a certain interior temperature I just set the heater control accordingly. My aircon stays off in winter.
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Good theory but how could it be a residual effect if the car has done several hundred miles in cold temperatures? According to the theory that the AC doesn't work at cold temperatures any residual moisture would have long gone wouldn't it?
In real life it just defies the logic I'm afraid. Mine stays on and works fine.
Dries wet feet out quicker too for some reason. Probably the de-humidifying effect which of course is also not possible apparently.
Anyway, it sounds like we are all best to do what we choose to and keep quiet. Don't want anyone hurting themselves...
:-)
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>> Dries wet feet out quicker too for some reason. Probably the de-humidifying effect which of course is also not possible apparently.
>>
It is possible. As I said, it is due the cold and already dry air being heated, and that reduces its humidity further, and so you get the "AC effect" but without the AC compressor on.
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I can't switch the aircon off independently in my car. I can turn the whole heater system/aircon and fans off but not just aircon. There is no "aircon" button as such.
It's obviously not on when I've got the heater blasting away and at some point when I select a lower temp, the aircon kicks in. But it's something the car decides, not me.
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>> please explain why it is then, no matter how cold it is outside, that my
>> car demists itself and keeps itself demisted far more efficiently with the AC on? It
>> just does.
>>
Here is my thesis:
When you say AC is on, is this with outside temperature below 4°C and the compressor is still on? (if the compressor is OFF, by definition the AC is OFF).
Or do you mean that your car heating-ventilation is in the mode that cars without AC option would be, i.e. blowing fresh dry cold air from outside over a heating it and then blowing it in to your car? Heating the dry cold air further lowers the humidity. This is why for a given set temperature (21°C seems popular with climate control users) the interior will demist while drawing in dry cold air but will mist up if you choose recirc function.
The cold dry air below 4°C serves the same function as air hotter than 4°C that has gone through the AC, i.e that the "hotter" (above 4°C) air has been chilled with the assistance of AC.
>> Is it perhaps the same reason why my diesel car is quite capaple of warming
>> itself up sufficiently at idle to de-frost the windows on a cold day despite that
>> being impossible too?
>>
Why is that supposed to be "impossible"?
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My car really is magic because it has two things that are impossible to have.
An aircon system that speeds demisting at any temperature and a folding roof that doesn't leak.
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>> Why is that supposed to be "impossible"?
Dunno, there were some posts on here recently arguing that. Mine heats up fine just as indeed all the diesel cars I've ever had have done.
As for whether the compressor is on or not I wouldn't know. One of our cars has climate control and the other has straightforward manual AC. In both cases they have a little yellow indicator light to show that the AC system has power running to it. I leave them both on permanently and find that works best for me. Not really sure if I care much how it does or doesn't work, it just does fine for my purposes so I'm happy !
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Same here: it's only off when I want to experiment with the misting phenomenon, or just before I park, to allow the residual moisture to be disposed of via the drain. That's supposing it isn't frozen, like the drain from the condensing boiler!
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>> to allow the residual moisture to be disposed of via the
>> drain.
It doesn't (and can't) all drain out. Some moisture remains until conditions are such that it evaporates. Imagine washing out a milk bottle and turning it upside down to drain ~ some will inevitably remain inside.
Last edited by: L'escargot on Wed 15 Dec 10 at 11:17
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Give it time and it will all drain out - I don't think the remaining amount will be very much in contrast with the puddle below the car in summer. Haven't noticed anything in the cold though.
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>> Give it time and it will all drain out - I don't think the remaining
>> amount will be very much in contrast with the puddle below the car in summer.
>> Haven't noticed anything in the cold though.
>>
Warm air retaines more moisture than cold, = more water under the car from the aircon drain.
Unless someone knows different of course.
Last edited by: Old Navy on Wed 15 Dec 10 at 11:27
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>> cars has climate control and the other has straightforward manual AC. In both cases they
>> have a little yellow indicator light to show that the AC system has power running
>> to it. I leave them both on permanently and find that works best for me.
Think of it as believing your TV is on when the standby light is on, or your central heating is on even when the room thermostat has stopped the boiler firing up. In other words, the main switch may be on, but the the device is in the off state.
If the compressor is off, decoupled, that means the AC function is off. Your heating & ventilation system is still on, but the AC part of it is OFF, in standby, waiting to cut in when the exterior temperature reaches your car manufacturer's outside temperature cut-off/cut-in set limit.
You are still getting a cooled/heated mix of air blown in to your car which has passed over a cooling/heating matrix and it will demist your car.
Now, anyone here want to take on the task in the global-warming/climate-change thread to educate forum members on the physics involved in that?
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>> If the compressor is off, decoupled, that means the AC function is off. Your heating
>> & ventilation system is still on, but the AC part of it is OFF, in
>> standby, waiting to cut in when the exterior temperature reaches your car manufacturer's outside temperature cut-off/cut-in set limit.
If I go into the CC settings and switch off the AC, I can hear the compressor switch off as well, likewise if I switch it back on the compressor starts running again along with a momentary dip in the engine revs, regardless that the outside temperature is in minus figures.
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>> If I go into the CC settings and switch off the AC, I can hear
>> the compressor switch off as well, likewise if I switch it back on the compressor
>> starts running again along with a momentary dip in the engine revs, regardless that the
>> outside temperature is in minus figures.
>>
In which case, your car manufacturer has designed a CC/AC system that does not decouple the compressor at low outside temperatures. i guess one way of achieving that could be by first passing all/some of the outside air over the heater matrix and then passing that air over the AC cooling matrix. The mix of air heated/chilled would be varied (via automatic variable fan speed) to keep your interior at the temperature set by you.
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>> If I go into the CC settings and switch off the AC, I can hear
>> the compressor switch off as well, likewise if I switch it back on the compressor
>> starts running again along with a momentary dip in the engine revs, regardless that the
>> outside temperature is in minus figures.
As it does with mine VxFan, but there are still people here convinced that it doesn't come on in winter. Maybe it doesn't in the latest cars. Still not convinced? Being a real anorak, I've actually got out of the car in winter and watched the aircon fan at the front of the car switch itself on and off in time with the compressor switching on and off. And being a rather sensitive anorak, I've felt my mouth getting drier when driving in winter with the aircon on. Now if anyone would still like to convince me it's not working, be my guest.
:)
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As a mere, semi-technical female here, may I put forward a suggestion that a tad of confusion is being caused in this argument by some of the more technical among us not knowing if they have air con or climate control?
I have watched this thread with amusement.....the crv's stays on, and works, all year round whatever the temperature:)
Pat
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I have alway left my aircon switched on permanently, whether it is doing anything is a different matter.
Last edited by: Old Navy on Wed 15 Dec 10 at 17:21
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>>I have watched this thread with amusement.....the crv's stays on, and works, all year round whatever the temperature:)
So have I. Mine was switched on when I bought my car eight years ago, and has never been switched off. Works perfectly.
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Are me and Dave the only ones having a quiet snigger at those who haven't read all this thread?
(Tue 14 Dec 10 19:20)
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>> Are me and Dave
Dave as in me, or Dave as in Dave?
I read it, hence my post today at 11:03
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OK.
Me, Dave and the other one with the tutu. ;>)
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Quick update here...
The problem still persists. Today, driving it was above 4C so the compressor was on (snowflake on digital display). Windows clear. Outside temperature then dropped below 4C and the compressor disengaged (snowflake went off). Within 20 seconds the car was badly misted up. I am thinking now that when the compressor is off the air entering the cabin is moist, more moist that the outside air. Any ideas if this is possible and if so causes? TIA
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It shouldn't be misting up so badly that quickly. Are you sure that your recirculate mode isn't jammed in the 'on' position? If I leave mine on recirculate too long it can start to mist up quickly.
EDIT - have you checked that your bulkhead isn't full of water? Maybe somethings blocking the drain holes, so you're getting a lot of moist air into the car.
Last edited by: corax on Sun 2 Jan 11 at 17:51
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Thanks Corax, the setting for recirculation of the air is definitely off, so no problems there
The area under the wipers appears dry (ie under the plastic grill at the bottom of the windscreen), is that what you meant?
Last edited by: PR on Sun 2 Jan 11 at 17:56
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>> Thanks Corax, the setting for recirculation of the air is definitely off, so no problems
>> there
No thats not what he said, he said are you sure its not jammed? Is the servo operating the flap?
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When Fiat had it 3 weeks ago they said it was operating all flaps ok.
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>> The area under the wipers appears dry (ie under the plastic grill at the bottom
>> of the windscreen), is that what you meant?
Yes, thats the place, the pollen filter is located there sometimes, I thought it might be damp, but it sounds alright. Your carpets in the footwells aren't damp? What about the boot under the false floor? It sounds like your car may have a water leak somewhere through a faulty seal maybe.
Edit - Yeah that's what I meant zero. maybe the recirculate is jammed on. You shouldn't feel much air through the vents if on another setting if it's jammed.
Last edited by: corax on Sun 2 Jan 11 at 18:18
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All carpets and mats are dry. Pollen filter is new. Plenty of air coming through the vents. Boot spare wheel well dry.
From what happened today I would *guess* that the source of moisture is the incoming air.
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your air is different than ours then.,
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Trade it in come summer :)
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Sorely tempted at the moment. Its 3 years old with 94k on it and has been great. Never had such problems in the past, even in cold weather.
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Air needs to be warm to retain moisture, as per aircon drain puddles under cars on hot humid summer days.
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When I had this problem my pollen filter was full of damp leaves. Cleaned out and it's not done it since.
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Cheers rtj70, pollen filter is new (see post 1)
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You're assuming it was done of course ;-)
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Yes they gave me the old one. I know the foreman there so I trust him!
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The outside temp was around 2.5C, and it was dry (dry roads, no rain, mist or murk). The incoming air was warm enough, car was up to temp.
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So if you've checked there are no leaves in the pollen filter then scrub my idea.
No idea where it would be in your car - in my Mazda6 it bolts up behind the glovebox somewhere.
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Its around knee area in driver "footwell", on side of centre console on the Bravo
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Could your aircon drain be blocked with mud or road crud ?
Last edited by: Old Navy on Sun 2 Jan 11 at 18:57
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My thoughts aswell, though it seems to work ok when outside temp is high enough for compressor to be engaged. Would this be the case with a blocked drain?
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>> The outside temp was around 2.5C, and it was dry (dry roads, no rain, mist
>> or murk). The incoming air was warm enough, car was up to temp.
>>
What temperature do you heat up the interior to? It seems that the moist air in your car (wherever it is coming from) is condensing on the cold surface of your windows, so logically your windows would seem not to have been well warmed up.
Have you tried increasing the blower speed using manual control?
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Temp was set to around 19C. The windows were cold, as the outside temp was low (2.5C). The moisture in the air did indeed condense onto the windows but the question is why either the incomng air or the air in the car is so moist.
Have tried all settings at various stages over the last few weeks, nothing works.
Last edited by: PR on Sun 2 Jan 11 at 19:07
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>> question is why either the incomng air or the air in the car is so
>> moist.
>>
cold air is dry air, so the sources of moisture are
# within the car cabin (you, damp pollen filter, air-recirc jammed on, etc. of which the only one we have not eliminated is you!).
# outside the cabin (air-con condensate getting sucked back in to cabin).
>> Have tried all settings at various stages over the last few weeks, nothing works.
>>
try setting the temperature to 22C or 23C for a few runs.
p.s. I take it this is you posting on
www.fiatforum.com/bravo/255041-misting-up-windows-2.html
Last edited by: John H on Sun 2 Jan 11 at 19:21
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It is indeed :)
Have tried that aswell. Went on a run from here in Middlesbrough to Liverpool on boxing day, approx 2 hours. Had to run with window open at times it was so bad.
I dont think its me either, as this doesnt happen in my Alfa!
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>> Went on a run from here in Middlesbrough to Liverpool on
>> boxing day, approx 2 hours. Had to run with window open at times it was
>> so bad.
>>
Hmm...that does sound pretty bad. Both old model and new Honda Jazz we've had will mist up if the a/c is turned off, and my Merc will mist after a while which threw me until I realised the a/c shuts off gradually. But once the car is warmed up both will run fine in this weather with a/c off.
Someone else mentioned that perhaps the car is stuck in recirc mode but you can easily test that by trying both positions and the extra noise in recirc will be obvious. Maybe it does something weird like go into recirc mode in cold weather to try to warm the interior faster?
I wonder if there could be a problem with air extraction - some cars have flaps over the outside of the extract vents that might get stuck or perhaps they're in the boot area and are blocked by junk in the boot??
Last edited by: Bill Payer on Sun 2 Jan 11 at 21:57
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>> The problem still persists.
I'm not at all surprised.
>> Outside temperature then dropped below 4C and the compressor
>> disengaged (snowflake went off). Within 20 seconds the car was badly misted up. I am
>> thinking now that when the compressor is off the air entering the cabin is moist,
>> more moist that the outside air. Any ideas if this is possible and if so
>> causes? TIA
>>
The moisture that the aircon extracts from the incoming air doesn't all drain out of bottom of the unit. What you are experiencing is the residual moisture being brought into the car by the airflow through the unit. Mine does exactly the same if I use the aircon in winter and then switch it off. My solution is not to use the aircon in winter.
I explained this phenomenon on 14th December, and suggested a way of proving it was the case.
Last edited by: L'escargot on Mon 3 Jan 11 at 14:22
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>> The moisture that the aircon extracts from the incoming air doesn't all drain out of
>> bottom of the unit. What you are experiencing is the residual moisture being brought into
>> the car by the airflow through the unit. Mine does exactly the same if I
>> use the aircon in winter and then switch it off. My solution is not to
>> use the aircon in winter.
>>
>> I explained this phenomenon on 14th December, and suggested a way of proving it was
>> the case.
>>
No, Les, that is not it. If that was the problem, it would go away after a few miles. As PR says "Went on a run from here in Middlesbrough to Liverpool on boxing day, approx 2 hours. Had to run with window open at times it was so bad." Read PR's thread on Fiat forum and explain why he is experiencing this problem now after years of trouble free climate control use.
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Also from the end of November for 3 weeks the temp here didnt go above 3 or 4C so the system was not in use for that period at all. Problem still there..
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When I was in the car A/C business, I used to see a few of these cases every year. The moisture on the windows has to come from somewhere. Some will come from the residual moisture on the evaporator, although there isn't usually that much when it's very cold out. It should also diminish within a reasonable period of time.
Invariably I would find something wet in the car. Moisture only comes from wet things, and the warmer the car gets, the more water evaporates making moisture on the cold windows. When you stop, the car rapidly cools down inside, and the water stops evaporating.
So I think you need to have a good look for the source of moisture. Lift all the carpets (they will feel absolutely dry on top, even when there is 1/2" of water underneath), boot carpets, check seats, pollen filter, pollen filter housing, all around the lower air ducts, bottom of the door inner panels, behind kick panels, around roof pillars, around the inside of the bulkhead, up behind the glovebox, spare wheel well, pockets in the side of the boot etc. Somewhere you'll find water where it shouldn't be.
Another quick test you can do is put a couple of fan heaters in the car for an hour or 2, somewhere like on the front seats pointing toward the footwells, and see if you have the same problem. Even a very small amount of water or damp wil make a hell of a lot of condensation.
Last edited by: Dave on Mon 3 Jan 11 at 16:34
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I think you're right Dave. Somewhere in that car it is wet, so everytime he goes out and it warms up, the moisture from whatever is wet is steaming the car up. Every car where I've had misting up problems it is down to something that is damp in the car - carpets, boot e.t.c
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Thanks for that Dave / Corax, Im starting to think you are right. Had the engine undertray off today to see if there was any blocked drains etc.. but all looked in order.
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PR, what happens if you just use the heater, and not the aircon, for an extended period? I'm asuming that this mode is possible in your car. As I said, I get the problem you describe if I use the aircon in cool weather but it eventually goes when I use the heater only. If what Dave and corax says is the cause and I too had damp in the car the misting should continue ~ but it doesn't.
As it happens, using the heater only is my preferred setting because I don't see the point of cooling the air with the aircon and then heating it up again with the heater.
Last edited by: L'escargot on Mon 3 Jan 11 at 18:49
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L'escargot, the Fiat system has a button with a snowflake on, which has a light to signify if it is on or off. When it is on and the exterior temp is >4C there is a snowflake symbol on the digital display screen.
If the exterior temp is <4C you can have the button on or off, regardless of which the snowflake in the display is not there, signifying the compressor is not engaged.
I have attempted running with this switch off even at exterior temps <4C and it has not made any difference, though admittedly only for a brief period.
If you have time....(post 4 link, its on P50 onwards...!!)
www.fiatforum.com/bravo/171718-bravo-manual-pdf.html
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>> As it happens, using the heater only is my preferred setting because I don't see
>> the point of cooling the air with the aircon and then heating it up again
>> with the heater.
The point of using AC in conjunction with the heater is because it makes for a far more efficient demister because of the dehumidifying action of the AC (well in most cases anyway). As you use a dehumidifier in your garage, you of all people should understand how it extracts moisture.
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>> most cases anyway). As you use a dehumidifier in your garage, you of all people
>> should understand how it extracts moisture.
>>
Just one of the idiosyncrasies that young L'escargot displays. :-)
He is set in his ways, constrained by a hardened shell. Witness the fact that he will put up with a foreign language IE8 rather than try out Firefox.
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>> Just one of the idiosyncrasies that young L'escargot displays. :-)
>> He is set in his ways, constrained by a hardened shell.
On the contrary. I analyse problems and take action as necessary to eliminate them. I might not have a high degree of computer literacy, but I'm able to solve window misting problems in my car. If something gives a problem (like using aircon in cold weather) I look for (and generally find) an alternative which doesn't give the problem.
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>> The point of using AC in conjunction with the heater is because it makes for
>> a far more efficient demister because of the dehumidifying action of the AC (well in
>> most cases anyway).
I just set the heater to maximum temperature, maximum fan speed, and all air to the windscreen and it demists my windscreen quickly. When the windscreen is clear I reduce the temperature to my desired level, I reduce the fan speed to my desired level and alter the air distribution as I require. The vents on the fascia keep the side windows clear. The electric rear screen heater takes care of the rear screen. Being in control of individual functions works for me.
PR, have you tried this technique? If so, what was the result?
As I've said before, in my car using the climate control in cool weather results in misting when I switch it off. So, I just don't use the climate control in cool weather and I don't have a problem with misting. Just because my car has climate control doesn't mean I have to use it.
Last edited by: L'escargot on Tue 4 Jan 11 at 13:20
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Putting max fan and max heat onto the windscreen does clear it, but as soon as I reduce this it starts to fog up again. Also the rear windows arent touched by this, ie, they remain misted up.
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>> Putting max fan and max heat onto the windscreen does clear it, but as soon
>> as I reduce this it starts to fog up again.
You'll probably have to persist until all the residual moisture in the aircon unit has dried out.
Last edited by: L'escargot on Tue 4 Jan 11 at 13:50
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>> Just because my car has climate control doesn't mean I have to use it.
Using it in mine means I can keep the fan speed to a minimum, and not blowing like a hurricane.
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>> >> Just because my car has climate control doesn't mean I have to use it.
>>
>>
>> Using it in mine means I can keep the fan speed to a minimum, and
>> not blowing like a hurricane.
>>
It seems that we have two groups. Those who insist on using climate control in winter regardless of the result, and those that don't. Ne'er the twain shall meet!
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>> It seems that we have two groups. Those who insist on using climate control in
>> winter regardless of the result, and those that don't. Ne'er the twain shall meet!
>>
One of those groups consists entirely of L'escargot and Bill Payer. I suppose they also share something in common as far as their young age is concerned. :o)
BTW, Les, if your car mists up after having used CC as you describe, then there is probably too much residual moisture being blown back in to your car. Something wrong with your system. What does your owner's manual advise you to do with CC in winter?
Last edited by: Suppose on Tue 4 Jan 11 at 14:20
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>> >> It seems that we have two groups. Those who insist on using climate control
>> in
>> >> winter regardless of the result, and those that don't. Ne'er the twain shall meet!
>> >>
>>
>> One of those groups consists entirely of L'escargot and Bill Payer.
Fame at last!
>> BTW, Les, if your car mists up after having used CC as you describe, then
>> there is probably too much residual moisture being blown back in to your car. Something
>> wrong with your system. What does your owner's manual advise you to do with CC
>> in winter?
The manual doesn't say anything specifically about winter use. It just says switch it off when it's not required ~ which is what I do. I'm happy to just use the aircon manually for cooling in summer, and the heater manually in winter. I like to be in control of the individual functions.
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>> BTW, Les, if your car mists up after having used CC as you describe, then
>> there is probably too much residual moisture being blown back in to your car. Something
>> wrong with your system. What does your owner's manual advise you to do with CC
>> in winter?
>>
I do make a point of running mine from time to time, indeed I mentioned earlier that I used it, and it worked at 1C in the Jazz the other day. I just don't see any point is using it if it's not needed - you wouldn't, for example, leave the heated rear window on all the time.
I do find though, that if there's any hint of dampness in the air, you can't turn the Jazz a/c off once it's been on. New model is just the same as the old one was in this respect.
The Merc is s bit wierd as the the a/c runs at a reduced capacity for a few mins when its turned off so it'll seem fine, then gradually start to mist up. This also causes a problem that the "trick" of turning the a/c off a few miles from home to dry out the system doesn't work.
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>> you wouldn't, for example, leave the heated rear window on all the time.
>>
My wife does. It drives me to distraction when I get in a car after she's used it.
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>> you wouldn't, for example, leave the heated rear window on all the time.
Mine switches itself off after approx 15 mins.
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>> >> you wouldn't, for example, leave the heated rear window on all the time.
>>
>> Mine switches itself off after approx 15 mins.
>>
The one in my Merc does, but surprisingly the one in wifey's new Jazz doesn't appear to.
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>> It seems that we have two groups. Those who insist on using climate control in winter regardless of the result...
I don't insist on using it. Vauxhall recommend it be run regularly, and as it uses no more fuel with it on and helps keep the windows from misting up, it makes sense to use it.
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>> Using it in mine means I can keep the fan speed to a minimum, and
>> not blowing like a hurricane.
>>
I find the problem in both our cars (new Honda Jazz with full climate control and Merc C Class) is that, once up to temp, the auto setting runs the fans too slowly for my liking. Hence I generally operate both systems manually.
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>> >> Outside temperature then dropped below 4C and the compressor
>> >> disengaged (snowflake went off).
>>
I can't recall another car where the snowflake (or other indication) goes off when the a/c shuts itself down due to low temp.
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The light on the switch stays on, but the snowflake disappears (then re appears when temp goes above again), quite nifty ;)
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>> The light on the switch stays on, but the snowflake disappears (then re appears when
>> temp goes above again), quite nifty ;)
>>
Are you sure that's not just telling you it's potentially icy outside?
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OK, I've read the instructions now and it is just saying the compressor is off.
I would try extending the test of L'escargot's suggestion and running with the compressor (and therefore AQS and recirc) switched off. Try opening the rear windows a touch to get some air flowing through the car. I don't use the auto climate in either my Merc or wifey's Jazz.
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...also, just occured to me that I took wifey into work this morning in her Jazz. Started the car and it immediately misted up. Pressed the front screen demist button and it cleared in a few seconds as the a/c came on. Displayed temp was 1C.
Strikes me that if the a/c in your (and others) cars suddenly shuts off at 3-4C then it's almost bound to mist up in cold wet weather as the condenser releases its moisture. This is clearly :) potentially dangerous.
Last edited by: Bill Payer on Tue 4 Jan 11 at 10:18
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Yes I know what you mean, but this is more than that.
For example again this morning, temperature below 4C so no compressor engaged from start to finish of (17 mile journey). Car was clear to start with but by the time I got to work (approx 30 mins) the back windows were all steamed up. This evening I will check under the carpets etc.. to see if there is some moisture anywhere. If that fails to show anything I will try the fan heater check (thanks Dave!)
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How many people are in the car? Human beings give off a lot of moisture.
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>> I don't use the auto climate in either my
>> Merc or wifey's Jazz.
>>
Great minds think alike.
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May be pointless but have you tried cleaning your windows?
Even in summer, if I have had air con on , when I switch it off the windows mist up until I blast the cold air onto them again. However if I give them a right good clean then they don't.
Also are your front and rear washers working properly? No chance of them leaking under the carpet somewhere? Do you have a sunroof, have you cleared out all the drainage holes at bottom of doors etc?
Just my tuppence worth
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Tuppence worths are all valuble, cheers BobbyG!
Windows are obviously quite mucky now with a daily soaking! Washers appear to be working ok, though they were frozen for about 3 weeks (and the misting was still bad so its probably not burst pipes!).
No sunroof
Will check under the carpets tonight...
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Right, so tonights updates in the ongoing saga...
Drove home from work (approx 30 mins in car) with heater system completely switched off (exterior temp 4-5C), NO misting at all. Now the car remained cold inside, so still could be damp source in car or heater problem.
Placed fan heater in car with clear windows. Left for 40 mins (heater cut out due to thermostat even on full switching off). Car was very warm inside, no hint of condensation anywhere.
Then took for a drive (for 10 mins) exterior temp 5C and heater on (no aircon).
Windows misting up again...
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So the source of the moisture is the car itself and it's not the aircon because it was not on.
Is there anywhere between the air intake and the inside of the car at all that has some damp material lying there like leaves. I'd say pollen filter but you say that was replaced. But this makes me wonder if they didn't actual replace it.
Could there be a leak somewhere which is putting moisture in the system?
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Once had this problem with a car and evemtually discovered water trapped in the spare wheel well where presumably the previous owner had left the boot open in the rain. Pulled out drain plug, dried the compartment off, put the plug back, no further bother. Might be worth a look.
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Yes, checked that too. Bone dry. As I said, I heated the car up probably warmer than usual with a fan heater, no trace of condensation at all.
Last edited by: PR on Tue 4 Jan 11 at 19:52
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The scuttle panel is clear and dry (the bits I can see anyway, havent taken it off).
I opened the pollen filter housing again this evening and without taking it out (hard to slot back in!), it felt dry.
I am wondering if the air con drain pipe is blocked, but despite being under the car yesterday I couldnt locate it...
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>> I am wondering if the air con drain pipe is blocked, but despite being under
>> the car yesterday I couldn't locate it...
>>
It may be low down on the engine side of the bulkhead, if you shine a torch down the back of the engine you may see it.
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Could it have a small leak in the heater matrix (apologies if this has already been suggested).
Andy
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There is zero loss of coolant.
Looked all over for the drain, including taking the engine cover off to see better behind it, nothing! I have asked on the Fiatforum aswell, no joy yet!
Last edited by: PR on Tue 4 Jan 11 at 20:45
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>> Could it have a small leak in the heater matrix (apologies if this has already
>> been suggested).
That would usually result in coolant escaping and running down into the front carpets. It might, however, have a leak so small it's only evident when the system is under pressure - by then it is pushing out steam.
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>> small leak in the heater matrix
>> might be ... so small it's only evident when the system is under pressure ... pushing out steam
To confirm if this is the case, when the windows mist up, wipe the mist off the inside of them with a cloth. If it's coolant (containing antifreeze) condensing on the glass it will be slimy and difficult to clean off completely without smearing. If it's rainwater it will be relatively easy to buff the glass to a mirror shine.
>> between the air intake and the inside of the car
>> As I said, I heated the car up probably warmer than usual with a fan heater, no trace of condensation at all
Have you tried blowing air through from the intake outside the car (with a hairdryer perhaps?) This would confirm if the damp were within the pollen filter/heater blower system at least, and not the boot etc.
Last edited by: Dave_TD {P} on Tue 4 Jan 11 at 21:31
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I will check the windows for residues but my first thought would be that it is water.
Good idea on the hairdryer, would need to find exactly where the air intake is though.
I may be able to get my hands on a moisture meter from work, if so I will check levels in the car and outside, to confirm the heater is worsening the humidity..
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I have found this schematic of an auto climate system from a Stilo, I am assuming the Bravo layout will be very similar, the centre fan housing certainly looks like it!
Anyway, does anyone know what a "dehydrator filter" is, I have never heard of this, see link item 2 I think it is...
tinyurl.com/2u77efk
Last edited by: PR on Tue 4 Jan 11 at 22:31
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>> Anyway, does anyone know what a "dehydrator filter" is, I have never heard of this,
>> see link item 2 I think it is...
It's the same thing as a receiver/drier unit, all car A/C systems have one, it's purpose is to remove any moisture/dirt from the refrigerant which would otherwise damage the seals/compressor.
Last edited by: corax on Tue 4 Jan 11 at 22:45
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Is it a consumable? I know the pollen filter should be changed, how about this dehydrator filter?
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No its not a consumable. Its in the pressurised gas side of the system. And being there, it has no bearing on cabin air flow.
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Cheers Zero, yes I now know it removes moisture from the coolant itself.
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>> No its not a consumable.
That's not strictly true. The unit on my car is supposed to be replaced when the refrigerant is replaced. I did mine because I had a leak at the connections (the thing was a work of art, an alloy bowl tig welded at the ends), but the aircon engineer didn't seem too concerned about replacing it regularly. I think the only time you really need to do it is if the system had been open for any length of time, which will saturate the dessicant in the unit with moisture.
My dads Avensis needed a new condenser, and the receiver/drier is incorporated within this, so there is no way of replacing it unless you're changing the whole condenser. So in this case it would not be a consumable.
Last edited by: corax on Wed 5 Jan 11 at 10:01
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>> Then took for a drive (for 10 mins) exterior temp 5C and heater on (no
>> aircon).
>>
>> Windows misting up again...
>>
Assuming the heater works by air blending, the logical conclusion to draw from your tests is that there is moisture in the route the air takes when heat is selected. I have to say that seems unlikely to remain for a considerable period - it would surely dry out on a long run (when it wasn't raining) and you've ruled out heater matrix leaking.
The only other thing I can think of is that there's so little airflow through the car that your own breath is misting it up! Is it worse with 2 people in the car? Is it a 4 door vehicle and have you tried running with the rear windows open a touch?
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Has the heater matrix been checked? Seems to be known Fiat issue.
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Well I was in the car for 30 mins earlier on with no heater on and there was not one "drop" of condensation anywhere....
Heater matrix leak would surely lead to loss of coolant, even slowly. The coolant level hasnt shifted for 3 months.
Havent ran with rear windows open. I think your theory of the air picking up moisture from somewhere is more likely the cause
PS its a 5 door harch
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Right, might be getting somewhere now (finally I hear you all say haha).
I got a hygrometer from work.
Drove home in the Alfa, rhumidity at around 30% in the car. Went to gym on way, then drove home from there (v sweaty and hot!) with air con off and humidity peaked at 33% (windows were clear).
Bravo arrived home (its the GFs car btw). She had had the aircon on, windows were clear. Humidity was a similar 30%.
I then turned the compressor off and the air immediately jumped to 53% humidity and the whole car misted up. The humidity of the air (at the vents) then slowly fell back to 29%, but by then no chance of clearing the condensation without a compressor to de hydrate.
My conclusion is there is a drainage issue, any water removed from the cabin is returned in one "lump". I need to investigate fully the drainage situation
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>> My conclusion is there is a drainage issue, any water removed from the cabin is
>> returned in one "lump". I need to investigate fully the drainage situation
>>
Let us know the result.
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Will do L'escargot.
The drain in question I now know goes from the heater box through an L shaped rubber tube into the floor (situated to the left of the clutch pedal in the side of the centre console).
I will disconnect this and place a beaker of some sort and run the air con, if the beaker remains dry then the blockage problem is in the heater box (gulp!) if the beaker fills the blockage is in the pipe taking the water out of the car itself...
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You may have trouble getting much condensation out in this weather. For extra effect boil a kettle in the car with the lid open and run in recirc mode.
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Thanks for the tip Dave. If the temp is high enough this evening I will try it from work (I am guessing there is plenty of moisture about in the car at the moment haha!!
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>>For extra effect boil a kettle in the car
And try not to let the neighbours see what you are doing...
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So after sticking a 500ml syringe on the rubber tube (that goes from bottom of heater box down and out of cabin) I can confidently say that there is no blockage there.
It appears then that there is no water coming down from the heater box, though will confirm after driving home...:(
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>> It appears then that there is no water coming down from the heater box, though
>> will confirm after driving home...:(
>>
Is the a/c evaporator in the same place, and using the same drain?
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I believe it is, after talking to the foreman at the Fiat dealer who said this is the aircon drain, there is no other one
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If there's no water coming down from the heater box, couldn't that indicate a blockage?
Could you connect a pipe to it and give it a blow. Any resistance could indicate a blockage and might even clear it.
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It does indicate something is not right. I will try and engineer a fitting to enable me to try that, thanks bathtub.
Im not 100% sure that no water is coming down yet, though from when I popped the pipe off the other day and found it dry as a bone Im almost certain there wont be any!
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I thought you said there was no blockage you meant you'd poured water down and it had come out.
I wouldn't expect there to be water draining through except in wet weather or in humid weather with the a/c on.
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Yes I meant there was no blockage in the "lower" part of the drain. Basically, there is a moulded plastic drain that comes down from the heater box. On the end of this drain is a piece of rubber tubing that then turns 90 degrees (so is effectively horizontal) before disappearing into the console and ending up exiting the cabin floor. I pulled this rubber tube away from the plastic drain, and proved that there was no blockage in this rubber tube. The plastic moulded drain (which comes from the heater box) is now the main culprit.
I have left the rubber tube detached from the drain and have placed a beaker under this drain. After my journey home tonight I will see if any liquid has gathered in this beaker.
Clear as mud? haha
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>> Clear as mud? haha
I hope you get to the bottom of this, because you really deserve to at this point. You're having such fun. I'm jealous.
:)
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Well as luck would have it it was 2C when I left work so no further on....
Funny thing is I really like the car!
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I think the first thing to do is establish whether the problem exists when you don't use the climate control, but just use the heater on its own. This might take some time to establish, in order to get rid of wherever your moisture is coming from when using climate control. I get a similar misting problem with my car when I use the climate control in cool weather and then switch it off, but not when I use the heater alone. It's not something just related to my current car because my previous car did exactly the same. Both cars did it from new. One question to ask yourself is whether the comfort level in your car is any different/better when you use the climate control in winter, and therefore whether it's really necessary. My heater on its own controls the car's interior temperature automatically, so I certainly can't see any advantage of using climate control. I personally don't notice the difference in humidity when using climate control, so to me there's no point. In winter the humidity of the incoming air is low as it is. I'm talking about the absolute humidity, not the relative humidity. science.howstuffworks.com/dictionary/meteorological-terms/question651.htm
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The system is an auto climate control. You can either have the system on or off. If the system is off you dont get any heating or fan or anything
If the system is on there are 2 options, have the compressor on or have the compressor off. If the compressor is off then it is dis engaged by a clutch, there is no alternate path for the air if you know what I mean.
The key now is to see if there is any water whatsoever coming down the drain from the heater box, I now need to wait until it is warm enough for the compressor to engage.
The car is booked in to Fiat for next Tues provisionally, but at the moment looks like a dash out jobbie
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>> The system is an auto climate control. You can either have the system on or
>> off. If the system is off you dont get any heating or fan or anything
Wow! In fact unbelievable. I wouldn't want that. I'll have to pay special attention to make sure that the heating/ventilation of my next car is as adaptable as that of my current car. It would be a major factor affecting my choice.
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But surely any car system is the same? You can have your fans and heater on or off on pointing in any direction, as can I. The point is that the compressor is either on or off, and if it is off it will simply be disengaged, not isolated in anyway.....unless I am missing something?!
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In my car I can use the heater on its own and set the interior temperature at which I want it to control or I can set it to uncontrolled minimum or maximum. The fan speed is entirely under my control.
I can use the aircon on its own manually or I can use it on automatic temperature control, with manual control of the fan speed in both cases.
Finally (heaven forbid that I ever would!) I could use the system on automatic climate control in which case the only option I have is to set the interior temperature. The fan speed is out of my control.
I got the impression from your last post that you couldn't use the heater on its own (with or without an interior temperature setting) with manual control of the fan speed.
Last edited by: L'escargot on Fri 7 Jan 11 at 10:25
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No wires crossed, mine is exactly the same (obviously cant set temp to less than exrernal without the compressor on however!).
I meant if you turn my system off (its a digital panel), then it is off. Once on you can have it on "Full Auto" or just "auto" (in Auto I can select fan speed, temp, direction etc..)
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I doubt very much if the drain is blocked, as the introduction of the pollen filters pretty much stopped this happening. If it was blocked, I doubt it will make much difference in the winter, as the amount of moisture removed from the air is minimal, and for it to evaporate back into the incoming air is next to impossible as the incoming air temperature is very low. The incoming air passes through the a/c evaporator first, so is at ambient temperature, and the evaporator runs at a few degrees above zero. The dew point of cold winter air is usually lower than the evap temperator, so that means zero moisture condensation on the evaporator.
Have you done the basics yet and checked for moisture under the carpets.
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The dealer last time checked under the front carpets but found nothing.
I also did the fan heater test, left it for around 40 mins (the heater reached its thermostat cut off point) and there was no condensation whatsoever
Last edited by: PR on Fri 7 Jan 11 at 16:19
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One further point, when the compressor was working the other day there was an extremely foisty smell coming from the vents. I know it hasnt been used much in a few weeks, but would this create such a smell?
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It shouldn't do. Mine doesn't ever smell, even if I've left it off for a few weeks.
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Right, doesnt appear to be a blockage out of the heater box. Although no water came out of the drain there was a fairly strong flow of cold air......
*bangs head against wall*
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>>*bangs head against wall*
Phone a friend...ly A/C repair company and ask them for their comments advice ?
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Done that, they werent particularly helpful, or rather didnt have any ideas.
Fiat said they can remove seats and carpets and pressure test for leaks. Sounds drastic to me
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Funnily enough on this wet day.
Today I sat in the car waiting for someone to come back, the air con was on before I turned off the engine, so was on when I started the engine again.
Guess what, the windows quickly misted up, and then cleared again. This has happened on all my previous cars with aircon.
Now I said 200 posts ago, that there was no problem. In my view you are chasing a problem that does not exist.
You can of course beat your hair out for another two hundred posts, but it wont be fixed then either. There is no problem,.
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Well these windows mist up when the air con goes off (or isnt on, from start of journey or when it goes off during a journey).......and they dont clear at all, so I cant see...
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>> Well these windows mist up when the air con goes off (or isnt on, from
>> start of journey or when it goes off during a journey).......and they dont clear at
>> all, so I cant see...
>>
I have difficulty believing that you can't clear the windscreen using the heater, and the rear screen using the screen heater. You've identified that the misting is associated with the climate control, so why not stop using it and just use the heater on its own? After a while ~ it may take several days ~ you may be pleasantly surprised to find that you no longer have the misting problem.
Last edited by: L'escargot on Sat 8 Jan 11 at 07:29
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As I have said previously, the car ran for around 3 weeks with no air con (heater yes, air con compressor, no) and this made no difference.
With the heater setting to max demist the windscreen is mostly clear (there is a festive looking border or mist around the edges) and part of the front windows also clear (the front 6" or so). The rest of the front windows and the rear windows remain misted, making it very difficult to see wing mirrors or side vision at junctions etc..
As soon as this max setting is disabled all windows start to mist up again. If you re engage this max setting (eg on a longish journey) then the car becomes unbearably warm (try setting heater to max for a long period in the car lol).
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>> As soon as this max setting is disabled all windows start to mist up again.
>> If you re engage this max setting (eg on a longish journey) then the car
>> becomes unbearably warm (try setting heater to max for a long period in the car
>> lol).
>>
Once the windscreen is demisted, can't you reduce the temperature and the fan speed, and adjust the distribution of the air, to keep the windscreen demisted whilst at the same time suiting your own bodily preferences?
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I've tried that, and you can slow the onslaught of teh misting, but doesnt stop it completely. The only time in the last month the car hasnt misted is when the compressor was on (in the last week mainly)
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>> The rest of the front windows and the rear
>> windows remain misted, making it very difficult to see wing mirrors or side vision at
>> junctions etc..
>>
I've mentioned this about 4 times now, but it really does sound like an airflow issue - air is not being extracted from the car at a great enough rate. I haven't searched for it, but it rings a bell that Fiats generally suffer from this?
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>> I've mentioned this about 4 times now, but it really does sound like an airflow
>> issue - air is not being extracted from the car at a great enough rate.
>> I haven't searched for it, but it rings a bell that Fiats generally suffer from
>> this?
I was going to mention this earlier, but now you've brought it up... Maybe these particular models suffer from poor airflow through the car. I remember Golf Mk2's and 3's were known for this. On a damp day, you could never get the rear windows to stop misting up, despite having the demist on full. The police used to moan about this with their Golf VR6's when they were full of people and gear.
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Its a recent phenomenon, 3 previous years of ownership have been fine.
How does a car's air come back "out", if a heating system is pumping air in, is there an opening somewhere, like an air intake?
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>> Its a recent phenomenon, 3 previous years of ownership have been fine.
>>
>> How does a car's air come back "out", if a heating system is pumping air
>> in, is there an opening somewhere, like an air intake?
There's usually a vent system at the back of the car to encourage through airflow. Sometimes it's pretty obvious like vents set into the D pillar or just behind the rear window.
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Cheers Corax, will mention that aswell. Ive got plenty to mention now haha
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>> Its a recent phenomenon, 3 previous years of ownership have been fine.
>>
>> How does a car's air come back "out", if a heating system is pumping air
>> in, is there an opening somewhere, like an air intake?
>>
As previously written:
"I wonder if there could be a problem with air extraction - some cars have flaps over the outside of the extract vents that might get stuck or perhaps they're in the boot area and are blocked by junk in the boot??"
As a test, try what I aslo suggested previously and drive with the rear windows cracked open.
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Yes sorry Bill Payer I remember that now!
One thing though, if cracking open the rear windows clear the mist it doesnt get me any further as to the cause of the misting does it? If it is coming from the heating system, the floor, a leak etc.. whichever it is this will I am guessing clear the misting, but it wont point to the culprit will it (unless I am missing something?!)
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>> I am guessing clear the misting, but it wont point to the culprit will it
>> (unless I am missing something?!)
>>
Well, my thinking is that there could be so little airflow through the car that it's misting just due to you breathing etc. You mentioned that it didn't mist up when you ran a fan heater in there but presumeably you weren't sitting in the car at the same time.
Running with the rear windows cracked open would, to my mind, prove whether the issue is air extraction related or not. If it does keep the windows clear then further investigation of the extraction system is warranted. On some cars they have plastic/rubber flaps on the outside- perhaps they're stuck? Have you cleared out the boot - on wifey's Jazz the extract from the car is on the lower inside of the hatch. Easy to cover it with a mat etc.
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>> Fiat said they can remove seats and carpets and pressure test for leaks. Sounds drastic
>> to me
If that's what your franchised dealer suggests, then it would be a good idea to go along with it. They ought to have more experience of you car's problem than anyone else.
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>> It shouldn't do. Mine doesn't ever smell, even if I've left it off for a
>> few weeks.
Yours must be pretty unique then. These pages, and those from the previous site are littered with comments about smelly aircon and what do do about it.
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>> Yours must be pretty unique then. These pages, and those from the previous site are
>> littered with comments about smelly aircon and what do do about it.
Yep, I guess I won't have to do anything about it.
Maybe PR has a dead rat down there or something.
Last edited by: corax on Fri 7 Jan 11 at 21:15
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>> One further point, when the compressor was working the other day there was an extremely
>> foisty smell coming from the vents. I know it hasnt been used much in a
>> few weeks, but would this create such a smell?
I got the impression that you used the climate control practically all the time, but now you say it "hasn't been used much in a few weeks".
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No, the compressor hasnt been on much in a few weeks is what I meant. And again, the compressor being engaged or not is the only difference...
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>> or just "auto" (in Auto I can select fan speed, temp, direction etc..)
>>
In other words "manual" then? :)
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When a car is as troublesome as PR's, sometimes the only solution is to sell it.
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If it continues that will be a consideration.
However, 3 and a bit years and 93k virtually trouble free miles is also taken into consideration. I like things to be right on a car, someone else might just open a window or whatever, I would rather it fixed ;)
As for the dealer, it does sound drastic but I will certainly go along with it. The car is out of warranty now though so I am being understandably cautious.
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Yes ;) it is indeed manual
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It really really really does sound you are stuck on recirculation mode.
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...It really really really does sound you are stuck on recirculation mode...
Dunno about his aircon, but this thread is definitely stuck on recirculation mode.
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Being a practical female I would go and buy a new pollen filter despite the old one appearing to have no moisture around it.
I would fit it myself and try it, if that didn't cure the problem I would then put the old one back in and keep the new one for sometime until a new one was due to be fitted.
I have seen this problem on a lot of Scania lorries, and without fail it has been down to the pollen filter.
The material is very absorbent and what appears to be dry may well be holding moisture.
The last time it happened to me I went to our fitters and asked for a new filter to be fitted. He checked the old one and said it was OK. I reminded him of how many times he'd said that before but still had to fit one to cure the problem. He agreed, fitted a new one, and the problem was solved.
It really would be worth a try.
Pat
Last edited by: pda on Sun 9 Jan 11 at 06:29
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Pollen filter was the first thing changed, so its now about 5 or 6 weeks old
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When you select recirculation mode there is a change in "noise" and airflow, which doesnt say that it isnt stuck in recirc mode but suggests that it isnt. How would you be able to tell definitively?
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Dunno
Maybe use one of those smoke bomb things you use to test chimneys. Stick it near the inlet scuttle and see if it comes out the vents with the fan on.
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I suspect the pollen filter would remove the particles?
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have you tried running it without the filter?
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No. With it being new and "feeling" dry I havent (yet) thought it necessary...
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Coming late to this - I have the same system as the OP in my Bravo. The only way round the misting problem in this sort of weather is frequent use of the Max button, setting the recirculate to "always allow air in", rather than the "let the car decide" anti-pollution setting and use temp on Mono at about 20.5, directed upwards, with minimum 3 bars of fan.
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Cheers Paulb, found similar, though I can never get the rear windows clear!
Heres an interesting one, in the following sequence of events...
Drove today with the compressor on, drain showed no moisture, as predicted as there is not enough moisture in the cold (5C) air.
When I got home (with clear windows) I turned compressor off (heating still on). Whole car steamed up in no time (as previous).
I re engaged the compressor, on re circ mode and there was plenty of water coming out of the drain (as expected, since the moisture content in the car was so high...)
So, if there was not enough moisture in the outside air to produce water in the drain, why the hell is there enough in the car once the compressor is disengaged?!?
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Can't answer that, but mine does exactly the same, so it must be a quirk of the design...
Regular treatments of insides of windows with Fast Glass or similar do help, though.
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Bit of an update...
Fiat had the car this week. Checked under all carpets and were dry (including boot). They then found a "substantial" water leak in the boot area. The water was coming in and ending up in the rear sill and the boot lid lining (so the spare wheel well was dry). They think it was coming in around the 3rd brake light (seal has gone). This has been replaced. They said to monitor. The air in the car is still damp so I put absorbing cat litter in last night and a long run or two with the compressor on should sort it. Will let you know!
Paulb might be worth checking yours out
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I'm pleased you seem to be getting somewhere.
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Good call PR - thanks. Reading back it does look like you had a worse dose of this than I did - mine's been bone dry inside all week, I suspect because the temp has been around 7-10C here all week and the compressor's been running. I'll keep an eye on the area round the 3rd brake light though.
In the spirit of Bravo knowledge sharing, yesterday I found that horrible metallic screeching noises coming from the front wheels on tight turns are caused by the brake backplate rubbing on the disc, so if you get that, that's what causes it. Dealer fixed FOC as part of the service I had done yesterday. Pleased about that, as I was bracing myself for new front brakes...
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Cheers L'es, hopefully this will sort it
Also cheers paulb, will bear that one in mind though not experienced that yet!
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Raise the flags of all nations, I THINK it is cured, and you are not going to believe what it was...
Anyway, there was a leak in the boot that the dealers found and fixed. I was filled with hope.
Imagine my disappointment when this did nothing..
A few weeks passed and I didnt have any time to sort anything. Then on sunday I decided to take the scuttle panel off. All looked dry as a bone, my heart sank. Then, inside the heater intake I noticed a flap, that was closed....(you are one step ahead of me here..)
Anyway, on pressing the recirc button on and off, no change to this flap, although as stated, the heater inside did change tone, so I am guessing the fan might change speed when it is engaged dis engaged. So I made sure the flap was open (though there wasnt much resistence), and re assembled. And immediately, the problem has gone. Drove to work with aircon compressor on then turned it off, nothing, windows clear as a bell.
Thank you all so much for the assistance on this lengthy thread, and to those who said it sounded like this earlier, I thank you. With the info from the dealers though it didnt sound like this was the issue. I suppose they plugged the thing into a computer which didnt show up any error codes, so said all was working as it should.....
Anyway, it will need fixing at some point properly
One thing I would say is the speed in which the moisture in the car has gone, I must say im totally surprised. It was a matter of minutes before all was clear.
Thanks again
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Have you noticed we are all logged on as you?
www.car4play.com/forum/post/index.htm?f=5&t=4888
Can you fix that now, please?
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Yep, stuck on recirculate.
And now to the important thing...
Why am I logging in with your username? And, apparently, dozens of other people. I know what you've done. You've cast a spell on us which transfers your problems to others - nothing to do with flaps.
I hope this doesn't mean I'll get in my car tomorrow and it mists up.
:)
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>>
>> Why am I logging in with your username? And, apparently, dozens of other people. I
>> know what you've done. You've cast a spell on us which transfers your problems to
>> others - nothing to do with flaps.
>>
We have become one, we are a collective conciousness :-)
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>> We have become one, we are a collective conciousness :-)
No its tron, we exist only in the machine...
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>> We have become one, we are a collective conciousness :-)
So I'll be condemned to a Borg cube for the rest of eternity :(
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Funnily enough, I am logged in as PR aswell, though I think that is ok for me ;)
All your posts are showing your own names, not mine.
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Now lets count back how many posts ago I said the recirc flap wasnt working, and more than once too.
sigh
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Yes, thanks Zero.
As I said though, dealer said they had checked operation, there was/is audible change in fan noise in cabin so not entirely predictable ;)
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Air con and cold weather - IJWS14
