Mildew Smell in A/C Vents?

SupaDave03

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2011 Mazda CX9 Touring
My wife drives our new 2011 CX9 so I dont drive it often. The other day I started it up and turned the A/C on full blast and smelled a slight mildew smell blowing right out of the A/C vents. It quickly went away but bother me as to why? My wife stated she has smelled that smell before but goes away almost immediately and never gave it a second thought. My wife also stated she only noticed it durning the hot part of the days when she first starts it up. I drove it this morning started it up and no mildew smell. Ill check again this afternoon when its hot, and see if I can smell that same mildew smell again. Also my car is very clean with only 5300 miles, any ideas or similar issues with your CX9. Thanks.
 
Have them check the cabin filter. Although the car is new who knows where it was stored. Dampness could have impregnated the cloth filter. I also had a mildew smell in my 6 and it turned out to be the cabin filter. Fwiw.
 
That's fairly normal this time of year. Being that it is so new, it's most likely just the condensation that is left on the evaporator when the car is turned off. That's why it goes away after a short period of operation once the evaporator starts to cool and remove humidity again.
Making sure your climate control isn't on recirculate when it is turned off on humid days can help to air out and dry the evaporator housing while parked. Leaving it on recirculate closes the housing off from fresh outside air during non-use and promotes bacteria growth housing causing the mildew smell.
 
Ya Im pretty sure thats what it was. I drove it this past weekend and didnt noticed it at all..Hmmm
Sure its a mildew smell? My CX-9 when new had sort of a chemically smell from the A/C - I guess offgassing from the plastic ductwork.
 
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