We have a 2005 VW Passat wagon and it has an awful and undetectable mildew/mold smell. We have had it checked for leaks by three separate mechanics, no water or dampness is apparent under the carpets, we have never seen any water in the car. It is not related to A/C or heat, for it is always there in the passenger cabin. We had it detailed with an antimicrobial solution applied to all of the upholstery and we cannot get rid of the stink. Help!!
Do you have a sunroof, by chance??
Two things to check: The A/C drain, and the sunroof drain.
On the Passat, the sunroof should drain by the door pillars (open the front doors, you’ll see a squiched tube looking thing). Use some bleach-water and clean the sunroof drains. Pinch open the tubes to get the water to flow completely through. Rinse it all clean with plain water, pinching the tubes to get it as drip-dry as you can.
I’d have to look at a Passat to see where the A/C drain is. Haven’t done that one before.
Thanks, we did have the sunroof drain checked to make sure that it drained adequately and didn’t leak into the car.
Have you had a good search through the trunk? Smells from there can often leech into the passenger compartment. Pull out the spare tire, and check under that, too.
Other that that, the only thing that comes to mind is that possibly the door drains have blocked, and there’s enough moisture in the doors to create some mildew. You can use a small piece of wire, and poke into them from the bottom to see if any are blocked. I’ll keep thinking on it.