I just purchased a 2013 Chevy Malibu LTZ and every time I turn on the air conditioner, there is this horrible odor of rotten feet that comes out of the vent. The longer I run it, the stronger it gets. Can you please tell me what is causing this and what I can do about it. I am still under warranty and I just purchased the vehicle from a dealer on the 28 of February. It is a certified vehicle and I still have factory warranty on it as well.

Thanks for any help you are able to give me.

  • Try changing out the cabin air filter with a carbon one. There is mildew in your system somewhere. Not sure if this will fix it, but it will surely help. Mar 15, 2015 at 11:29
  • 1
    I'd agree with Paul, it sounds like mildew. If you bought it less than a month ago, take it back to the dealer and make them fix it under warranty...
    – Nick C
    Mar 16, 2015 at 9:46
  • It might also be a small leak in the radiators - coolant can smell like rotten eggs. There are so many options best to take it back as it's so new to you. Mar 17, 2015 at 6:04
  • Do you live in a wet area, by any chance? If so, the mildew/bacteria explanation seems most plausible. This happens sometimes on collector vehicles that have stood for some time in regular contact with moisture (e.g. old garages).
    Jul 16, 2015 at 18:55

2 Answers 2


This is because bacteria live in your condition system, I'm from the EU so I can't recommend you a good cleaner for air condition systems, but I think in any good shop the salesman will recommend. And replace the air cabin filter. It's good sometimes before turn off car turn on heater to max for some seconds to dry possible condensate (where bacteria lives). There is a thousand videos on Youtube about this problem


I may be missing something, since I'd expect someone would have mentioned this. But, just in case: the standard answer to (I think) the same question on 'Car Talk' was always that the drain hose from evaporator pan was plugged.

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