Condensation on inside windscreen

[Gazwould]

All this is simple physics.

Car interior a higher temp or humidity to outside.

This warm air condensates on the coldest object, the glass.

 

[coolguy]

... Door seals and separate threads of wind noise from rear passenger door from incomplete seal? That's a possibility. ...

That's what I was thinking, I reported this problem a few months ago, they checked it out but said it was normal/part of the design.

Will mention it again to them next week when my car goes in.

 

[h5djr]

All this is simple physics.

Car interior a higher temp or humidity to outside.

This warm air condensates on the coldest object, the glass.

Basically the same as a building, except most buildings these days have double glazing. Ventilation is the biggest cure for condensation in building and I suppose the same is true for cars.

The full demising setting show normally only be used for a short while and then, as the Owner's Manual says "To prevent the front side windows from misting up in wet weather, we recommend opening the side air outlets, pointing them to the side and selecting the 'spot' setting"

 

[luadr1]

Is it washing up liquid ? And applied neat or diluted ?

Yes and it's applied neat

 

[Gazwould]

I'm going to conduct an experiment.

 

[luadr1]

I'm going to conduct an experiment.

any feedback'

 

[Gazwould]

Not yet as the same almost daily climatical conditions haven't repeated themselves.

I have been using a Bluecol anti mist which is supposed to eliminate interior condensation, well it's usually dripping wet so I think it's a chocolate tea pot unlike their rain repellent which is superb.

I coated the inside windscreen with the useless Bluecol then did a thin vertical of neat washing up liquid.

I can see potentially why it would work as it is slimey, scuba divers spit into their mask and using a finger spread and rub it over the inside area, then a quick rinse.

It works and this applies to swimming goggles too.

I'll report back my findings at a later date.

 

[mjcourtney]

I have the most wonderful image in my head of your windscreen covered in all kinds of gunge and slime now! lol

 

[JohnM100]

I have the most wonderful image in my head of your windscreen covered in all kinds of gunge and slime now! lol

Ditto. Reminds me of the Friends episode with Ross and the leather trousers....

Gazwould - respect to you for taking one for the team!

John.

 

[Gazwould]

Practically if the washing up liquid didn't work I was going to employ the local pikeys with strong cheap cider and cigarettes to gob on the inside of my windscreen.

 

[cuke2u]

I have no idea what you guys are referring to but I wouldn't let washing up liquid anywhere near the inside, or outside, of my car. It contains salt and could ruin the trims...

 

[0B1001001]

I can see potentially why it would work as it is slimey, scuba divers spit into their mask and using a finger spread and rub it over the inside area, then a quick rinse.

It works and this applies to swimming goggles too.

Naw, use toothpaste before use, no spitting please! Clean the silicone from the new mask and then leave well alone. Not that I'm suggesting you use toothpaste on your windscreen...

 

[Gazwould]

Toothpaste before 1st use of a mask yes.

Are you a scuba diver ?

 

[0B1001001]

Yeah but not for a while - mostly snorkelling and swimming now.

 

[Gazwould]

BSAC or PADI qualified ?

 

[Flugel Hound]

I see signs of moisture run/trails down the inside of my screen.
My car lives outside at all times and never use the aircon plus have sometimes had wet clothing in the car.

So from reading the above im a prime candidate. Will give it a clean and use aircon more.

 

[coolguy]

Well just been back from the garage and Audi have found nothing wrong. Just told me to keep and eye on the problem and if it happens a lot more/serious, they will book it in for a few days for observation.

Oh well...

 

[PilotAudi]

I see signs of moisture run/trails down the inside of my screen.
My car lives outside at all times and never use the aircon plus have sometimes had wet clothing in the car.

So from reading the above im a prime candidate. Will give it a clean and use aircon more.

Why don't you use aircon. It should be used on a regular basis or you will have problems .

 

[Joetidman]

Why don't you use aircon. It should be used on a regular basis or you will have problems .

I agree with pilot here, aircon is designed to be used all the time now, when not actually cooling air the compressor acts as demist. I've used it permanently in my scirocco with minimal impact on fluids and mpg

 

[cuke2u]

Yes leave it on, if you don't then the seals inside the AC will fail after a while. It is designed to stay on all of time anyway...

 

[cemerson]

I have my aircon on all the time too. I've tried a few journeys with it off but haven't noticed any effect on my mpg.

 

[Gazwould]

I have been using a Bluecol anti mist which is supposed to eliminate interior condensation, well it's usually dripping wet so I think it's a chocolate tea pot unlike their rain repellent which is superb.

I coated the inside windscreen with the useless Bluecol then did a thin vertical of neat washing up liquid.

I can see potentially why it would work as it is slimey, scuba divers spit into their mask and using a finger spread and rub it over the inside area, then a quick rinse.

It works and this applies to swimming goggles too.

I'll report back my findings at a later date.

It works,

a definate clear line where the washing up liquid was applied and buffed off.

 

[hopeless]

Aircon is not really designed to be on all the time but they are very reliable nowdays so keeping them on all the time shouldnt give too many longevity issues.

In fact not using the aircon at all is more damaging on the unit because the aircon gas/fluid contains a lubricant for the compressor and this needs to be circulated regularly or the unit seizes.

Oh and yes, it will affect the mpg, its a compressor being driven from a belt connected to your crank so its bound to sap some power.

To reduce condensation you could try some Bob Heath or similar visor/windscreen anti fog spray. Work great for motorbike helmet visors, I used to use it all the time.

 

[bobbinz]

Just to add a bit more confusion into the mix, I've got the steamed up glass too, however my A4 B6 Avant also has condensation on the metal inner skin of the roof above the head lining. And it's not as a result of sunroof drain issues, I don't have one. (Sunroof that is!)

My air con is suspect, but I can normally 'free' things off (sticking vents) within a few miles, I'll be getting around to changing actuation motors when things warm up a bit, no garage so I don't fancy freezing! But I suspect my headline condensation started as a result of the air con issue.

My point is, that if there is already a hidden source of moisture behind a panel or under a carpet, then this will be suficient to steam up your windows when you leave the car, particularly if there's a bit of sun and then a cool afternoon/evening to get the vapour moving and then condensing.

If you can find the source that's half the battle. Then you just have to sort out the cure! ...that's where I am ...I REALLY don't want to have to take out my head lining, but what's my alternative?

 

[wwfc]

I think you'll find problems with windscreen condensation is due to the fact that when you switch off the car with cc on , the 3 flap motors do not fully close. Therefore on cold windy days/nights air can flow directly thru the demister vent. If you select air to the footwells before switching off this should fully close demister vent and prevent condensation!!!!