Frost on inside of windscreen

Seamus99

I have a 17D1 Audi A3, I noticed in November 2017 that there was a lot of moisture on the inside of the windscreen and it was taking ages to clear. In January 2018 I noticed that there was frost on the inside of the windscreen. I got on to Audi North, they told me that they had not heard of frost on the inside of the windscreen before. They checked the car and told me there was no fault with it. In March/April I noticed frost on the inside three times, I took videos of these instances. I contacted Audi again and sent them the videos. The car was looked at again and again I was told there was no fault with the car. When I asked why it was happening they could not provide an answer only to say that if it happened again to bring it back. I would appreciate advice on what to do next.

salmocab

My wife had an issue with the inside of her windscreen being very wet, she got some moisture beads in a plastic container and it drew out the moisture over time. I know it’s not really what you were asking for but might be worth a try if your getting no help from Audi (her car was a Kia btw)

seamus

I've seen this plenty of times. Basically it comes down to the air inside the vehicle being too humid.

This can be down to incidental factors such as carrying a lot of people all the time, or moisture trapped in the soft furnishings. It's not a "fault" in the vehicle per se.

If possible, and especially with hot weather coming up, try and leaving the vehicle in the sunshine with all of the doors open for a whole day if possible. This should properly dry out any of the soft furnishings.

Second - do not use the "recirculate" setting on your AC. This is really only useful on insanely hot days in the summer. During the winter, recirculating the air will make fogging a million times worse. Always use air from the outside except for the first few minutes of a very hot day.

aaakev

Did you get the car valeted anytime before you noticed it the first time? If seats and carpets are washed and not allowed to dry fully before closing all the windows up you will trap moisture and it can cause this. It could also be a leak bit on a new car it is less likely to be this

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zilog_jones

Use the aircon in the winter to keep the interior dry - you can still use the heat with aircon on.

And clean the inside of the windscreen regularly with decent glass cleaner (not those crappy wipes!), as dust/dirt will attract more moisture.

R.O.R

Old sock, fill with rice (Tesco own brand will di, don't go splashing out on Uncle Ben's quick cook) and leave somewhere in the car.

Rice will draw the moisture out of the air.

Del2005

seamus wrote: »

Second - do not use the "recirculate" setting on your AC. This is really only useful on insanely hot days in the summer. During the winter, recirculating the air will make fogging a million times worse. Always use air from the outside except for the first few minutes of a very hot day.

I read this recently and couldn't believe it. My climate control is always on and it switches between recirculate and fresh air all the time. When I had manual AC I used to always use recirculation and never fogged up. Only time I fogged up was when using recirculation without the AC being on, and then usually because I'd forgotten to clean the windows, but they never fogged with the AC on.

zilog_jones

Aircon with recirc on does still clear the windscreen for me, but it takes a lot longer.

seamus

^^
AC works by removing moisture from the air, which speeds up the rate of sweat evaporation from the skin, making you feel cooler. So recirculated AC should be OK.

In the winter, unless you're one of those people, you won't be cooling the interior of the vehicle, so recirculating the warm air increases the humidity of the cabin.

Although the button in the car might say "AC" and pump out warm air, strictly speaking that's not AC. Modern climate control systems in expensive cars probably include all sorts of sensors to measure the humidity and temperature of the air in the system and vary accordingly. So recirculating the "warm" AC in winter may include a dehumidifier.

As a general rule, there's no need to recirculate except if you want to cool the cabin down extra quickly.

The quickest way to demist is to run the AC full blast on the coldest setting, recirculating the air and coming out only through the window vents.

zilog_jones

Whatever it's doing, aircon + heat is still dehumidifying and has worked fine in any car I've used (manual climate control). No need to be frozen out of it.

Pique

In older cars, replace the pollen filter too if you have this issue. Definitely helps. Wouldn't be applicable to OP, but still.

biko

Clean inside of windscreen really well. Moisture will cling to dirt.
Also don't touch the inside of the windscreen with bare hands or gloves, use a lint-free cloth to wipe it clean in the mornings.

bazz26

Had to look at the calendar there for a second when I seen the thread title.

Nforce

Had a few air-cooled Beetles in the past and frost on the inside of the windscreen was a feature of the marque!