AAA Car Doctor John Paul fields a question from a car owner whose air conditioner stinks. Not “underperforms.” Literally STINKS.
Q. My air conditioner stinks, not that it doesn’t’ work it actually smells terrible when I first turn it on. I have sprayed disinfectant in the vents and that helped a little but the smell comes back. My mechanic has looked at the car and couldn’t offer any suggestions. At this point I have resorted to putting air fresheners in the vents to mask the smell. Is there anything I can do?
A. The smell is caused by mold and mildew building up in the air conditioner evaporator coil and case. Short of disassembling the air conditioner and cleaning the buildup of mold there are a few things you can try. Liberally spray a disinfectant in the air intake of the ventilation system as well as vents- repeat as necessary. If your car has a cabin filter change it. If this doesn’t work I have seen professional kits that the technician drills small holes in the evaporator case so they can directly spray both a cleaner/disinfectant. There are also foaming cleaners that have gotten good reviews. Once the system seems back to normal avoid using the air recirculation setting and periodically insure that the evaporator drain hose is clear. Finally try shutting off the air conditioner a few minutes before the end of each drive and running the fan on high when you use the air conditioner. This will help dry out the evaporator coil and minimize the mold/mildew buildup.