A family member runs a mid-1990s car in which he finds the inside of the windows always covered in condensation first thing. They can be dripping wet.
A quick perusal down my street shows that older, say 8 - 10+ years old, cars seem to suffer this condensation to a variable but noticeable extent. Newer cars seem immune to it.
HJ wrote in a DT article last week that it was down to the plastic membrane behind the door card being punctured or just falling apart.
I'm not so sure - I think it may be down to the door & window rubbers hardening with age and so allowing in the cold damp night-time air.
Any views ? Any suggestions for a cure ?
Last edited by: Dulwich Estate on Tue 31 Dec 13 at 16:37
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The windscreen on my old Corsa used to steam up really badly, I changed the pollen filter and it made a dramatic difference. It was so blocked I think it was restringing the air going into the cabin making condensation worse.
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I expect another contributing factor is that these cars either didn't have air conditioning in the first place, or if they had it it's now broken, so the drying effect of regular use is not present. My LEC will steam up pretty quickly in very low temperatures if there are more than 2 people in it. The auto setting on the climate control assumes that AC is working I think, so when it cuts out there's not enough airflow to keep it demisted.
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Sometimes a sign of a water leak.
Older cars generally get less use, so more likely to be damp inside?
I've been using the MX5 when I can on dry days, once every week or two. Keeps it dry inside and so far it hardly steams up at all. Last winter it was hors de combat, SORNed for a couple of months, and by spring it had mildew in it.
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Both Astra F models we had were murder for condensation which took ages to clear. Replacing and then eventually junking the pollen filters made no difference.
Last edited by: Robin O'Reliant on Tue 31 Dec 13 at 16:55
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Dulwich, if the car in question is a daily driver, then I would suspect a leak somewhere, possibly even from the heater matrix, which commonly fail on older cars. The lack of AC on Oder cars makes drying them a lot harder.
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>>Sometimes a sign of a water leak.
I've had plenty of water leaks in older cars. If you haven't already done so, I would suggest removing any rubber mats and running your hands over the carpets.
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>>is that these cars either didn't have air conditioning
For air conditioning to be effective it has to be able to cool air in the car and heat air outside the car; The gas expands in the car absorbing heat from the air that is blown over it and then the gas is compressed outside the car radiating heat into the air.
Condensation occurs as the warm humid air hits the cooler radiator.
I do not understand how this can have any impact whatsoever on demisting a window if the air conditioning is not cooling the air in the car. If it is, then the air from the blower will conceivably be dryer than the air already around the windscreen.
What will impact the demisting of your window is the use of external air, which will be less humid than the air in the car, however you get it to the window.
Or am I missing something?
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>> Or am I missing something?
Dunno.
Worked today, wet people and wet dog in car, steamed up windows, aircon on - windows cleared.
I guess as long as your aircon can get colder than ambient it will condense.
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All I meant No FM2R was that any moisture that gets into cars with working AC would tend to be dried out when the car was used. I'm just hypothesising that older cars, which I suppose are also used less often, would tend to be damper inside than newer cars, all else being equal, and so more likely to steam up when parked. But I claim no expertise in the area!
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Keeping the inside of the glass clean makes a huge difference too. Dirt provides points of nucleation, or whatever the term is, on which water can condense. Clean glass gets less condensation to begin with and clears much faster.
I've noticed this since Mrs Beest became the regular driver of the S60. I frequently had to drive it into the morning sun on the way to work, so I was scrupulous about cleaning the screen. She doesn't bother, and getting it clear on a damp morning is now a chore as it never used to be. (CC still works well, so it's all about the glass.)
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>> Or am I missing something?
Yes.
Just cooling the air would make the problem worse, not better, because it increases the relative humidity (RH). For example, if the temperature in the car is 10 Celsius, and the RH is 80%, the dewpoint will be about 7 Celsius.
Forgetting the aircon for a minute, heating the air next to the window works because in reduces the RH even if the air being blown at it has the same water content as the air that was there before. From the above exmaple, if the temperature is 7 Celsius, and the dewpoint is 7 Celsius (so RH is 100%) then just warming the air to 10 Celsius will reduce its RH to 80%.
What's helpful about air con is that it removes water from the air it cools. The incoming air is blown over the evaporator (where the cold low pressure refrigerant is) and and as the ambient air is cooled water condenses on the outside of the evaporator. This is the water that you see dripping out under the car in hot weather.
If that same air is then mixed with hot air from the heater matrix in a typical air blend ventilation system then it will average down the water content of the recombined ambient air and hence its RH at a given temperature will be lower, and it will be able to pick up more moisture from whatever surface it is blowing over...demisting it more quickly.
E&OE. But that is what I have always assumed, given how air con works.
Calculator for playing with temp/RH/dewpoint - andrew.rsmas.miami.edu/bmcnoldy/Humidity.html
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>>What's helpful about air con is that it removes water from the air it cools.
But surely there will be no air to cool until the car warms it up. Which won't happen with the air conditioning trying to cool everything down unless you include the effect of your body and breathing which is, in any case, introducing more humidity.
So, I can't understand the potential impact int eh summer, but not in the winter. And in both cases it is presumably fresh (and therefore drier) air which is most useful, rather than "aircon'd" air, if you see what I mean - essentially the reason that condensation does not form on the outside of the window.
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>> >>What's helpful about air con is that it removes water from the air it cools.
>>
>> But surely there will be no air to cool until the car warms it up.
Well...maybe the air isn't going to get much colder but it is passing over a cold evaporator which will potentially condense some water out of it? Of course as soon as the air exiting the evaporator fins approaches freezing the aircon will switch off.
>> Which won't happen with the air conditioning trying to cool everything down unless you include
>> the effect of your body and breathing which is, in any case, introducing more humidity.
Initially the process is probably more effective on recirc anyway. The air will warm up quicker.
>>
>> So, I can['t]? understand the potential impact int eh summer, but not in the winter.
>> And in both cases it is presumably fresh (and therefore drier) air which is most
>> useful, rather than "aircon'd" air, if you see what I mean - essentially the reason
>> that condensation does not form on the outside of the window.
Don't forget the '"aircon'd" air will have a lower water content regardless of its RH than ambient air. It can also be blended with heated ambient air and the water content will average out at lower than ambient. And the hotter it is the lower the RH goes.
Condensation (often subsequently frozen) will form on the outside if the temperature is at or below the dewpoint. But if it's liquid you put the wipers on. If the temp out is above the dewpoint then no condensation outside, yes.
Condensation inside when there is none outside would be because the RH is higher inside, usually because the air has more water content (damp, wet carpets, people breathing...) or occasionally because it's colder inside than out - I think I observed this the other morning when the sun cleared the outside of the screen, but most of the car was in the shade and it was chuffing freezing inside.
Just hypothesising of course.
Last edited by: Manatee on Tue 31 Dec 13 at 21:10
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It's not heating it tht's important, so much as drying it - which is what the AC does. as soon as the engine is running, and the AC is on then it will be knocking the water out of the air on the evaporator. There are vents at the back of the car, so there is a continuous supply of 'dry' air - and you only need to drop the dew point just below the temperature of the glass and it will stop condensing out - even though you are not really that much drier! However, once the temp goes below about 2C it stops working, as the car cuts the AC.
Back to the OP - steamed up cars are almost certainly wet inside somewhere. However, I have had lots of older cars, and never had trouble with door membranes - even though I have been through most of them to get at door innards, so no idea what HJ was on! Door seals, windscreen seals, rear light clusters, pollen filters, sun roof drains are all common leak points. It's worth noting that the sound deadening under the carpets can absorb an awful lot of water before the carpet feels wet, and it almost impossible to dry without removing the carpet. Oddest one I ever had was on a BX where the trunking for the wires into the door had rotated a bit and was pinching in the door seal causing the water to run in! My Xantia has not been used for 2 weeks and is very damp inside....
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My Scoobydoo Forester mists up quite badly in the cooler weather, there's some water in the spare wheel area so I've removed the rubber bung to let the water drain away, I suppose I could always stick some cat litter type granules there to help soak up the moisture, but it's easier to just put the air con on.
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>> My Scoobydoo Forester mists up quite badly in the cooler weather, there's some water in
>> the spare wheel area so I've removed the rubber bung to let the water drain
>> away, I suppose I could always stick some cat litter type granules there to help
>> soak up the moisture, but it's easier to just put the air con on.
It might be better to find the source of the leak. Rear light clusters maybe?
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>>It might be better to find the source of the leak. Rear light clusters maybe?
Good thinking Batman, I'll check that out when it stops raining.
The other thing with my year of Forester is that the windows are pillarless, and, tbh, I like that and wouldn't want it any other way but, they're not ideal for keeping the wet stuff out of course.
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Could it be the boot seal? Try a bit of vasaline on the boot seals.
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>>Could it be the boot seal?
Yep, another area to check out, I've got a tube of silicon grease laying about somewhere.
I've not really bothered trying to find the source of the water in the spare wheel well tbh - out of sight, out of mind :)
My initial thoughts were the water was coming in via the sunroof seals and there may be a drainage channel that exits into the spare wheel well, I have some funny ideas sometimes.
:o}
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>> I've not really bothered trying to find the source of the water in the spare wheel well... out of sight, out of mind :)
>>
I took the same approach and finished up with a nasty puddle with the spare wheel rusty and the rest of my " stores" all soggy.
I thought I had solved the problem, a faulty seam above the rear lights.
It improved things but perhaps I needed more sealant.
I must check things out again when things dry out :-(
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>>I must check things out again when things dry out :-(
Have you not got a rubber bung in the spare wheel well, henry, that you could remove temporarily.
I must fess up to the fact that I didn't find the water myself, you see, although I look after the car, changing the oils, filters, etc. I still like to hand over wads of cash to a Subaru main dealer once a year,
and tis they who discovered the water :)
www.subaruforester.org/vbulletin/f75/water-spare-wheel-well-116773/
Last edited by: Dog on Sun 5 Jan 14 at 11:24
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>> Have you not got a rubber bung in the spare wheel well, henry, that you could remove temporarily.
>>
I may have but only ever baled out the water.
I will be forced to have a look as the jack stored under the spare is required.
One tyre is now flat. I think it is probably caused by the seal onto the old alloys failing ( again) and then the tyre going flat and making the seal worse.
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Ah!
"I noticed a bit of water in my spare wheel well while inspecting the accident damage with the assessor, but I'm pretty sure it's from the sunroof drains as I hear sloshing if it has sat for a few days with heavy rain. When I get it back I'll clean them out".
Lifted from that Subaru forum thread.
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I am bemused by the number of cars I see with misted up windows - old or new.
From the days of my youth , I believe the solution to be something called a 'cloth' or 'shammy' (or chamois, if you had a posh car)
Unless, of course, you don't care a monkeys about your view of the road
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>> Unless, of course, you don't care a monkeys about your view of the road
Frankly I don't. All those common little people mimsing about in their common little cars... the less I see of them the better. They can just stay out of my way.
EDIT: Terribly sorry. I don't know what came over me. A bit of Yuletide food poisoning perhaps.
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You know. that's one of the major things I miss about smoking. Even on the coldest mornings, one simply turned the engine on, retreated to the vestibule, sparked up while sipping a hot mug of tea and when the tea and tobacco were spent the car was ready to use.
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When I was a student, my car's windows (an Austin A35) steamed up regularly on Saturday nights.
Must have been perfume :-)
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>>Must have been perfume
I didn't realise you were the other way mad f.
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Those Minky cloths are very useful but my favourite toy at the moment is my Xmas pressie from younger brother - a Karcher Window Vac. If my car is a bit steamy then a quick minute with the vac does the job.
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The Minky, is he the businessman?
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Have you got a leesonce for your minky?
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Stop it, I've got a cough !
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>The Minky, is he the businessman?
No. He's the accordian player's assistant.
www.youtube.com/watch?v=93ZDOcU2TL4
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Thats torn it Kevin. I expect I know every line from every PP film but I still corpse at most of them.
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From my sample of 4 cars:
Those kept in a garage don't steam up. The one that lives outside does.
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The Note doesn't steam up but the Vitara sometimes does. It was a lot worse when the windows had some crap, probably silicon, sprayed on the inside. I attacked it recently with surgical spirit followed by some stuff filched from under the sink. Yesterday in the rain I parked at a caravan showroom just on the edge of the Pennines. The rain must have been a lot colder there 'cos the old girl was steamed up when we got back to her after an hour.
I guess jumping in and out with wet coats on must build some moisture up in the seats. I normally leave the windows down a quarter of an inch in this weather.....seems to help without actually raining in.
The Jowett heater is useless, as is the blower. It's no fun to drive in wet conditions.....so I don't if I can help it !
We didn't buy a new van either....deciding to spend a few quid on tickling up the present '99 Elddis Broadway. Had a nice lunch at a Toby carvery, though.
HO
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>>
>> Yesterday in
>> the rain I parked at a caravan showroom just on the edge of the Pennines.
You bin to Goodall's/Lowdham's at Crosland Moor?
Did the Floating Light on the A62 ever reopen? ISTR it closed about 10 years ago...
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When I left my car on station car park all day light steaming inside was inevitable when a sunny winter's day turned to frosty evening. That's just life. Needed a few minutes running to get warmth and evaporate the mist.
Heavier condensation - droplets - proved to be a symptom of Xantia shipping water through tailgate and soaking the boot carpet.
A peculiar characteristic of aircon cars is a flash of condensation onto clear glass when a/c is selected after car has been parked for an hour or so. I guess this is due to water droplets in the evaporator being carried through the heater matrix, certainly clears again as soon as it appears.
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Bromp's condensation flash happened to us in the Note on the M6 toll. A sudden downpour made the windows colder and SWM hit the aircon button, thinking it would help keep the glass clear.
The whole car steamed up in about 3 seconds and I couldn't see a thing. It was in the lap of the Gods where I ended up. As it was I had to slow right down and stay in lane...I couldn't see behind and I was trying a lane change at the time to get to the toll booths. The lane I was in led me off down to the A5.....better than piling it up !
HO
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>> You bin to Goodall's/Lowdham's at Crosland Moor?
>>
>> Did the Floating Light on the A62 ever reopen? ISTR it closed about 10 years
>> ago...
>>
Nah, didn't go over to the dark side...Glossop Caravans, where we bought this one.
Don't know about the Floating Light. I used to go to work that way and it wasn't open then but that was years ago. Last time I went to Hudd, to have lunch with a lady friend, I went on the train and she met me at the station.
HO
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Has anyone tried stashing bags of silica gel around the cabin? Been thinking of buying a job lot of them for our cars and giving it a go. They mist up in the driveway, particularly the older Golf.
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>> Has anyone tried stashing bags of silica gel around the cabin?
Alternately, cat litter under the front seats. In bags though, not loose.
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Hmm. If it's in a bag, how will the moisture penetrate the bag and become absorbed in to the litter? Does the stuff come in paper bags or some such? I have no idea, as the only way I like cats is served with noodles and soy sauce. Maybe sweet chilli.
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Well you either leave the top of the bag open, not so much in that the contents spill out, or use something like a deep litter tray instead.
Mind you, loose cat litter in some people's cars probably wouldn't be noticed anyway ;)
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>> Well you either leave the top of the bag open, not so much in that
>> the contents spill out, or use something like a deep litter tray instead.
>>
>> Mind you, loose cat litter in some people's cars probably wouldn't be noticed anyway ;)
>>
Should one take ones shoes orf ?
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>> Did the Floating Light on the A62 ever reopen? ISTR it closed about 10 years
>> ago...
>>
Probably more than ten years.
It's now a private residence.
Neil
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I've thought about going down the silica gel route. I suppose you would need a few big bags and then remove them from the car daily and microwave them dry.
Wiping the windows with a cloth / sponge / chamois leather and leaving it in the car probably isn't the best way either - you'd want to wipe off the moisture and keep the wet thing away from the car interior. Perhaps rotate a pair of them with one sitting on a radiator at home.
Or, buy a new car !
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if you wipe the inside of windows with a demist cloth and then leave the cloth in the car surely the moisture will find its way back to the window surfaces over night/ during the day especially if the glass has been warmed by the heaters?
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Ahem:......"and keep the wet thing away from the car interior"
Agreed !
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Has anyone tried any of the anti-fog/anti mist products for either windscreen or visor? I'm thinking of buying some- any recommendations?
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>> Has anyone tried any of the anti-fog/anti mist products for either windscreen or visor? I'm
>> thinking of buying some- any recommendations?
>>
For helmet visors a Pinlock Insert comes recommended on most bike forums. This video from MCN explains how to fit -
www.motorcyclenews.com/mcn/news/newsresults/videos/2013/may/may0313-video-pinlock/
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The sensor thingy on my windscreen had misted up sufficiently last night to cause the automatic switching from main to dipped beam to malfunction. It even posted an apologetic message on my dashboard to that effect.
Which was all very well, but I had to revert to manual operation of the dipped and high beam stalk which was jolly inconvenient what?
;-)
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Windows steaming up - particularly in older cars - RattleandSmoke
