I’ve been having this awful mold smell coming from my 3rd gen during the first few minutes of AC use in the warmer weather months when I generally use AC more often. This mold smell rarely happened in the winter since I usually only use heat without AC and the air circulation is usually set to “outside” instead of re-circulate. So I’ve read somewhere to simply not use the default re-circulate setting when operating the AC to avoid the mold smell, and if using the re-circulate – to only use it to initially cool down the car then switch to outside circulation. Some also state while the AC is on outside air circulation to turn off the AC a couple of minutes before arriving to your destination while keeping the fan on, but mainly I see that simply using the outside air circulation resolves my odor issue. Keep in mind, that the default setting for AC while cooling down the vehicle is to re-circulate when using the “auto” mode – so you’ll have to be cognitive about switching it to outside air each time. This method works like a charm for me. It has been driving me nuts for two seasons. Since following the above, I’ve not had that stinky mold/wet sock/hamper smell coming from my vents. I hope this helps others with the same problem.
Do you perform at least yearly (especially after the winter), periodical AC disinfection and cabin filter replacement?
Have you change your cabin filter and when was the last time you replaced it? To keep it smell nice and fresh, I recommend you spray some cologne on the filter and let it run for 5-10 mins. See below link for how to change your Gen cabin air filter.
I have the same problem in my 2010 Prius and the cabin filter is spotless so far. Furthermore, I have the same problem in 2006 RAV4, but not in 2003 Corolla. Interesting, Toyota came out with a fix for stinky AC in RAV4 and published as TSB sometime in late 2009. Unfortunately, by the time TSB came out, I was outside the 36 months of warranty and was screwed up. Sound like the same will happen with the Prius. It was some serious fix: http://ww2.justanswer.com/uploads/johnduh/2010-04-02_042552_T-SB-0378-09.pdf
Toyota has the A/C refresher kit for $20 or you can simply try this method. How to clean your Evap core for the summer without having to take out - 6G Celicas Forums
Do you leave your A/C on even when you turn the vehicle off? I had the same issue with the smelly A/C when I got my '08. I noticed if I turn off the A/C down the street from my destination, the outside air can come in and I no longer have the smell anymore. If that doesn't work, try replacing the cabin air filter and use an air conditioning cleaner/deodorizer. Hope that helps. iPad ? HD
If you have mold in your ducts, it's possible there is a leak in the evaporator unit. Putting in a new filter, spraying cologne, or changing circulation settings isn't going to get rid of the problem or the mold. It's just like mold in your home air ducts- you need to locate and fix the source, then kill the mold (not just deodorize it). You can treat it yourself with products in auto parts stores or online, like Klima Cleaner or Wurth A/C & Heating System Treatment. But I'd recommend having your evap looked at by a mechanic to check for leaks, because the mold will just keep coming back.
I just used my AC system(car is not even 2 month old), and I thought I noticed a slight smell already. I know this is an issue with E46 BMW and various other BMW model due to lack to proper moisture management in the AC system. I hope that's not the case with G3 Prius too! Ugh..
If there are leaks there would be freon (or a substitute) leaking.....and I wonder if mold likes to grow on freon. Mold like moisture......in fact it needs moisture to survive. When you live in a damp area, the temperature of the evaporator area will go well below dew point of the air. It gets wet.......mold like that. The water should leave the car through the drain, but that can be blocked. When you switch off the AC and let it circulate over the evaporator to warm it up and to dry it, the mold will die.
