Horrible damp smell upon start up

[Dionlewis]

Hi All, 

this issue started out a couple of years ago and was only triggered by using the AC, I would use the AC and then when switching back to regular air the windshield would fog up pretty bad along with a bad smell, This is still an issue to this day, and requires me to be tactical when using AC.

 

however more recently the damp smell has found its way in to the regular climate control system, and after start up the smell is pretty bad but will go away after a few minutes of driving. 
 

I took apart the scuttle panel last week and did find a large amount of trapped water/leaves/dirt sitting around both the wiper linkage and ECU. I cleaned both areas out as best I could, and was hoping that this was the cause of the smell. A week later and it seems to be ineffective, I’ve tried turning the heat to maximum in the cabin to dry everything out that way, all this did was cause the MMI screen to start glitching out presumably due to overheating. 
 

I’m at the point now where I’m wondering if it’s ever worth bothering with it anymore or if it’s just a lost cause, it’s just a little sad as it’s only just ticked over to 90,000 miles (3.0 TDI 2011 model)

when I first got the car in 2021 there were very little codes that would pop up that list has grown exponentially. 
 

I’ve not had any trouble with water making its way into the footwells, but sometimes just the general feeling inside of the car is a bit muggy and the seatbelts will feel slightly damp to the touch. 
 

I’ve not got a sunroof that could be causing this.

 

if anybody has any steps that I could take to try and alleviate the problem I’d be very appreciative. 
 

I’ve attached a video just to show what I was dealing with in the scuttle panel blockage. 

 

 

[Steve Q]

Have you checked the pollen filter housing? 

When was the AC system last regasssed? 

Is there any water in the wheel well? 

Is there condensation on the inside of the vehicle when you get into it in the morning? 

[cliffcoggin]

Dion.

There will be a drain for condensed water from the aircon casing, which is why there are often water drips on the ground when the car is parked after a drive in humid conditions. There is a good chance your drain line is blocked. I don't where it is or what form it takes, but you will need to find and unblock it.

[Marcin Z]

Hi, I've cleaned the leaves and dirt from the same section in my car recently (just as a preventative maintenance and not due to any issues) and it did not look anywhere near as wet or moist as it does in your video, so as others have said there may be a blocked drain somewhere.

In relation to damp smell, I've had a similar issue in another car (not Audi) and what helped to get rid of it was one of those air con cleaners, which is a small canister that you put in the car and set off with AC/ventilation on full blast for about 10 minutes (it is like a mini smoke bomb). I was sceptical about it before, but in my case it sorted out the damp smell from the air con for good. That said, I don't think it was as bad as yours, as I was not experiencing damp seatbelts or windows fogging up. So you may well have other issues, but for the sake of less than £10 it may be worth a go (I think I bought the aircon cleaner for less than £5 a couple of years ago).