What's the musty smell coming from my A/C vents?

I have a 2008 Mazda CX-9 that only has 2,000 miles on it. The air blowing out of the vent has a musty smell to it initially, until I turn on the A/C. Without having to bring it back to the dealer, why is this happening and how can it be corrected? I live in humid Florida, so maybe the condensation from the A/C doesn't dry out. Any help would be appreciated.

Rick, Delray, Fla.

We know dealership experiences can be less than thrilling, but in the case of something like this you probably want to take it in, especially if it only has 2,000 miles on it.

As you mentioned, it may be excessive condensation, possibly caused by a clogged drain where condensation is getting trapped and festering. It could also be twigs, mud, damp leaves or even a rodent that kicked the bucket near the HVAC air intake, which is commonly on the passenger-side cowl under the hood.

If you really, really want to avoid the dealership, you could take a look under the hood near the cowl to see if any crud has collected near the air intake for the HVAC system. Depending on how mechanically comfortable you are digging around in your car, you could also find the cabin air filter — if it’s equipped with one — and check for any debris caught in the filter that could be causing a questionable odor. Any air that’s drawn into the car through the HVAC system will be filtered through the cabin air filter, and it may be located in a place that can collect outside debris.

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Answered by Joe Bruzek on January 16, 2008 in I'm Just Wondering | Permalink

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