Damp smell after rain, suspecting windscreen

[timk]

Hi,

I'm trying to figure out a damp smell that happens every time it rains heavily. The car doesn't have a sunroof but it has had a windscreen replacement at some stage as it has a non-genuine one fitted now:
"AUSTRALIAN AUTOGLASS DOT459 AS1M644 ACOUSTIC 0 ***"

I know I am suffering from confirmation bias but the install seems to be pretty bad, they've reused the damaged side moldings and the plastic at the bottom doesn't click in properly.

I've cleaned out the drains in the front wheel arches so I don't think it is that.

The BCM was freaking out back in Nov 2024 but it has behaved since then, I'm not sure if it got wet but there wasn't anything obvious. Opening up the case doesn't give any clues.

There's no signs of wet carpets or leaking door grilles.

Any ideas or opinions?

Thank you!

[DV52]

timk: Tim- Hi.

Hmm.......... wild guess - but are you absolutely sure that this problem ONLY "happens every time it rains heavily"? And a second question - is it your practice to use the air-conditioner to clear the windshield from fogging-up?

I ask because since you say "There's no signs of wet carpets or leaking door grilles" - the other (likely?) reason is mold build-up on the evaporator-coil for the air-conditioner that lives behind the dashboard. Mold build-up can often be interpreted as a wet carpet smell and it's particularly prevalent if you drive the car in a humid climate (which I assume is the case here because you are talking about heavy rain in a summer period)

So, if I'm correct - there are many ways to deal with the problem from commercial solutions to DIY fixes. The solution that I use is set the fan to low speed and then spray "Gelen-20" into the external air vents under the windshield. It's important NOT to use a mold inhibitor that will react with the delicate veins on the evaporator. As I said there are commercial products for this task that I'm sure are available from your local car shop!

Don

[Lucas_R]

Check in the boot area around where the spare wheel is, as the Golf hatchbacks are known for getting leaks from either several spots such as:

- rear hatch rubber weather seal
- taillights seal
- rear hatch wiring grommet

Generally if you have water leaking through the hatch area it will be pooling down around where the spare wheel is.

Otherwise your windscreen might be an issue. When I had a Mk6 I had to get a new windscreen fitted by O'Brien glass and they fitted some low quality aftermarket glass. My wipers shuddered and you could see the glass was warped or wavy if you looked from the right angle, and whenever it rained I got condensation on the inside of the windscreen. Thankfully when I approached O'Briens with this info they agreed to replace the windscreen. The replacement windscreeen was much better and no more leaks or issues.