Galco

In an effort to give back to the community, thought I would share my inexpensive DIY fix for a musty smelling A/C system.

The last time this happened my 2006 was still under factory warranty; but well beyond the 1st year. There is a TSB on this as it’s a somewhat common problem but Audi only warrantied for the 1st year of ownership. The factory remedy requires and ultrasonic mist generating machine to disinfect and deodorize the system, and the service costs about $120-$180 at the dealer. Alternatively, for less than $15 (delivered), I purchased the 1Z Klima-Cleanser (Easy to Use version).

1Z Einszett Klima-Cleaner (ETU) Easy-To-Use

After a few weeks the musty smell is greatly reduced but not eliminated. I plan to do another treatment and will report back.

Here’s what I did:

1. Followed the combined directions on the Klima-Clean can and input from Audi’s TSB – with car running and ALL windows, doors and sunroof closed, fan on high, lowest temp setting, air routed to front vents only, recirculate on, econ on

2. Place can on floor of passenger side aimed toward front of vehicle and under the dash where the return air for the system is located; also suggest cardboard under can (see picture in TSB of the Audi’s recommended placement of the ultrasonic misting device) http://ww2.justanswer.com/uploads/as...938_ANSWER.pdf

3. With the car running, activate the can of Klima-Clean and close the door immediately – the smell is pretty strong so avoid inhaling

4. Let the can completely discharge, takes about 5 min – do NOT open the car. Let the chemical recirculate inside the car for another 10 min or so.

5. Shut off the car and open all window and sun roof to air out the car before driving for another 20-60min to minimize the smell as, like I said, it pretty strong and uncomfortable

6. Word of caution, the propellant in the can will discolor your interior – to prevent cover the area around the can placement in plastic wrap. Unfortunately, I didn’t secure it well enough and during the process the plastic wrap fell and yep, my glove box got a rash (see pic). Next time, I will secure the plastic wrap with some blue painters tape.

7. I was able to remove the discoloration with some of Sonax Dashboard Cleaner (good product BTW) and all is good now.

Hope this helps others.

MP4.2+6.0

All makes sense for what you mention. But I typically never get past earlier steps that do it for me--

1. Make sure A/C is even charged or it gets musty when it isn't eliminating the build up efficiently. BTDT/experienced on D3 until I got a system recharge and found it >50% depleted.
2. Clean plenum drains and under plenum plant debris that lead to build up of organic material. Combine with water, and rotting smell being pulled in through outside air via the filter area.
3. Replace the charcoal activated HVAC filter periodically, and make sure the replacement isn't a down market one w/out embedded charcoal.
4. Clean front rugs once in a blue moon so it isn't sucking used sock and shoe smell when pulling from interior. And especially, make sure they aren't wet or musty. Hence even in SF Bay Area w/out snow or year round rain, the rubber mats go in once the rainy season is pronounced.

Panelhead

For me, fixing the drains for the evaporator core fixed this issue. Look underneath after running the AC for a few miles. Should have two water puddles from drainage. Mine got so bad that I could hear water sloshing around and got drippage inside.
I will get my AC checked, seemed to be fine, but like you mentioned, it still works when low of charge.

DiagnosisUnknown

Good thread. Thanks for sharing. I've spent ~$500 at the dealer and still have a musty smell in my car. I was thinking of parking on a hill with the car nose pointing down and pouring a bottle of alcohol into each of the vents and hoping it goes down the condensation drain. Probably not the best plan but this is annoying.