AutoTips Fresh Air Tips

For those who live in humid areas, a common complaint is a musty odor from the air conditioner or heater, often after the car is parked for a while. One cause of this is moisture left in the drain pan after the heater or air-conditioner is shut off.  Many U.S. cars run the air-conditioner in the defrost position to remove moisture from the air, so your air-conditioner (a/c) compressor may be running even in the winter.

What to do: There are many different remedies people have used, you can try this one for free. The key is drying out the air-conditioner before you shut the car off.

American cars: In the winter, if you don't need the defroster, run with the controls in the heat or vent position, possibly for the last few blocks before you park your car. On most American cars, this will bring in fresh air, and give the pan around the air-conditioner a chance to dry out. In the summer, for the last few blocks before you shut off the car, run with the a/c off, and vent on.

Cars with a Fresh or Re-circulate lever (found on many imports): Be sure the lever is in the fresh position for winter, and if you don't need it for extra cooling, the same in the summer. Often these cars have a switch to allow independent control of the a/c compressor, so you can merely shut it off a few blocks before you stop the car.

Other Possible Causes: Air Conditioners in cars generally have a hose to drain off the condensation from the air conditioner coils. If this hose becomes plugged, water can collect in the air conditioner area and take a long time to dry out, permitting molds, etc. to grow. The drain hose is normally on the engine side of the firewall, and may not always be easily accessible to clean out. You may need to take the car to a dealer or auto shop to have this cleaned.  Leaks in the air conditioner condensate area onto the carpet can leave damp spots for mold to grow.

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