I get a nasty smell almost like dirty socks from my AC but not all the time . I have changed the cabin filter .

 

GM made a spray for AC smells - it's caused by mold buildup on the evaporator coil. You can pretty easily get to the coil from the cabin-filter housing opening. You might try spraying it off with some clean water with a few drops of bleach added, followed by clean water.

 

Try spraying Fabreze aerosol can (not the spray bottle) into the recycle inlets with the AC running.

 

You want something something like Einszett Klima Cleaner http://www.autogeek.net/1z-einszett-...freshener.html. I've used this on some of my older cars, and it's worked great to get rid of the smell.

 

Check to make sure the drain isn't plugged. It's the rubber hose you see going into the bottom of the footwell. Jam something flexible in there or pour water in there to make sure it comes out under the car.

 

i have this faint smell .. kind of like paint or something...

can't figure it out...

 

I've used the 1z Einszett Klima Cleaner in several cars as well, with good results. Of course, like wrinkledpants mentioned, best to make sure the drain isn't plugged.

Here's one review that may be helpful>>

"I used this on my 2003 BMW 325i that had the standard "Old musty BMW death smell" in the AC. It seemed to do a great job considering how bad my car was. I went from seriously wanting to vomit when i would put anything other then heat on, to being bearable. I'd say in one shot it got rid of 75% of the smell, which is REALLY good considering i had and EXTREME case of built up funk in the evaporator coil from the previous owner(s). I had to use Lysol in the vents itself since i wasn't comfortable with spraying the foam in anything other then where the evap coil was. But that's where most of your stink grows anyways. And the Lysol got rid of most of what was left. But don't read into that too much, like i said my case was extreme. For most smelly AC' I'm sure one shot will do just fine.

I only gave it 4 stars because i felt like it could of been a bigger can. In addition they don't tell you that you need to stop and shake it continuously while emptying the can, otherwise the amount of foam coming out and the velocity diminishes quickly.

EDIT: 1/21/2014....

Ok here's an important follow up from my initial review. The smell came back about 70% after about two weeks. I tried the Einszett bomb, and all that did was make my interior smell unbearably like chemical for a week. So at my whit's end, I ordered another can of this, but THIS time, I read up online on how to remove everything under the hood enough to actually physically see and touch my AC evaporator (It's not as hard as you would think!!), and this time I could visually ensure that the foam got into every nook and cranny of my AC evaporator, and it did!! Afterwards, because I was doing other work under the hood at the same time that caused me to have to leave the car off, I didn't run the fan after 20 mins like the can says. It sat in there, undisturbed, for about an hour before I ended up starting my car and running the fan for the first time. That was 3 weeks ago. And from moment one after doing this it smells absolutely brand new!! Zero hint of any odor. Even after cycling the AC on and off on a hot humid day (We've actually had a few of those here in VA recently). I've TRIED to make it smell again, and I cannot replicate the issue!! So the moral is, if AT ALL possible, do not shoot blindly into yrou vents with this. Get to your evaporator as much as you can and visually watch and ensure that the foam gets on every inch of your evaporator and it will me time AND money well spent!!!!"

 

This might help as well...

http://cayenne.insanegarage.com/diy-...ystem-cleaner/