Arizona Auto Repair

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Stinky smell from air vents and slippery transmission

I saw an article of you in the Southwest Valley Republic where you answer questions for consumers and I actually have two if you can possibly help. First off I drive a 2007 Chevy Impala LT. I recently moved here about 6 months ago from Indiana so I’m not use to needing to use my A/C in the car that much. Now that I am in Arizona I use it almost all the time and the past month or two I have noticed a very musty smell….almost like spoiled milk coming from the vents. It’s not all the time but typically the warmer out the more I notice it. Sometimes it is only noticeable for a few minutes and other times it’s noticeable for the entire trip. My car is kept clean and I use air fresheners but this smell will not go away. The only thing I can think is that there is moisture somewhere inside and the water is getting stagnate. I just thought I would see if this is an issue you have heard of before and if so what would it cost to fix this?

My other question is an issue with what I am assuming is something wrong with my transmission. When driving I will come up to a stop and then when I go to take off it feels as though the transmission slips very rough at takeoff. It has got progressively worse but it’s not terrible and no check lights have come on. The transmission fluid is full so other than doing the obvious and taking it to a mechanic to look at it I have no clue what it could possibly be. I suppose I am putting it off because I am new to the area and don’t want to take it somewhere that will take me through the ringer. Any advice would be much appreciated!

Ryan Martin

To your first question, chances are there are dirt and debris in the evaporator core. There is a service that can be done to clean out the inside of the evaporator box (inside the dash) that involves a foam that gets sprayed into the evap core housing which helps dissolve the dirt and debris. Additionally, the evap drain can get clogged up, which gives you the musty smell. Changing the cabin filter may help as well (same basic idea as the air conditioning filter in your house).

As for the second question–that’s a little harder without being able to inspect and test drive the vehicle. It can depend on many factors including how many miles are on the car, when the transmission was last serviced, and the condition of the fluids. It’s possible it might not even be a transmission issue. I would advise you take the vehicle to a reputable shop so they can duplicate the problem and give you and accurate diagnosis. Visit to find a reputable shop in your area or ask a trusted friend for a referral. Don’t be afraid to get a second opinion.

Chris Garman is President of Wilhelm Automotive ( To ask a Car Care question, please email Chris at [email protected] Please include your name and city for publication purposes.


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