Check your frunk. I notice odours from the frunk can get drawn into the cabin.

I stored my car a couple of winters ago and to prevent critters from settling in, I left an open box of fabric softener sheets in the frunk. Took about a year for the smell to dissipate from the car interior.

 

The mildew smell comes out of the vents only when the AC is on

 

Make sure you're turning your AC off 1-2 minutes before shutting off the car so that your HVAC system has a chance to dry out.

My wife always leaves her auto climate on in her van, so I have to treat it with this stuff every year or two. Works great!

https://www.1z-usa.com/klima-cleaner...l-application/

 

How best to clean drain lines?

 

anyone? The smell is still coming out of the vents, I've done practically all of the above.

 

Have you purchased the AC cleaning solution that I linked above?

 

Two questions:
1) Do you park outside or is the car stored in a garage?
2) Is the smell persistent of just for the first few minutes when you get going?

I have a similar problem with my cars that I park outside, but it's only for a few minutes at startup.

 

Yes!

 

I park outside, and yes it is persistent but very mild, I smell it on my clothes when I get out of the car.

 

Did it make any difference at all? Some people find they have to do 2-3 cans of that stuff

 

Two things, park the car in a different angle, condensation builds up in certain angles. My tesla model 3 does this when I don't park in my garage. Second, leave windows open if you can.

 

My old VW GTI did this quite a bit, I bought a can of Ozium and misted the car, shut the door with the AC running for 5 minutes so the mist would cycle and it helped a lot, not a permanent fix but if you are out of options it may help.

 

Had the exact same problem with my Cayenne (12 model with 60k miles). The dealer did the recommended cleaning and the smell is gone. Now occasionally on my 911 (2014, 25K miles) it's starting to smell. The odor is from where the condensation exits the vehicle via a couple of rubber tubes that seem to meld together at times, which creates mold, and hence your smell. You can either take it to the dealer for the recommended service on the AC which occurs every two years, and that should take care of it or try and do it yourself. The dealer charge is somewhere in the 300-400 range for this recommended service. I've done a small bit of research on the 911 as to where those water vapor tubes are located, but have not been able to isolate the location based on my exact model so I can do it myself. I live in Colorado so the AC is not on all the time, hence no smell. But like many others have mentioned, just turn the AC off for a few minutes prior to arriving at your location and that should help. My dealer suggested exactly the same procedures. Not sure if that helps or not since my wife does not do that in the Cayenne and it has not started to smell yet since they serviced it.

 

I am ready to do any service that is possible, my dealer did not know what can be done, what is the "recommended service" that you are referring to? I did change the whole evaporator and it costed me 5000k USD, so I am not sparing cost, the smell is not going away, I am starting to think should we not sue Porsche for this poor AC design?

 

The dealer referred to cleaning out the system with Frigi fresh...See attachment of their service write up...