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Q: Trying to stop outside air from coming into my car

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How do I prevent outside fumes (from other cars) from coming in through the air conditioning/heater vents? The owner's manual says to put the A/C on Max A/C, but that doesn't work. Most other vehicles have a button that shuts off outside air, but my car doesn't. Any tips?

A: The Max A/C setting should close the fresh ...

The Max A/C setting should close the fresh air vents off, preventing fresh air from entering the climate control system, but there is natural ventilation built in every vehicle so it is impossible to completely seal the vehicle from outside air. If the Max A/C setting does not close off the fresh air vents, then the function of the fresh air flaps need to be checked. A professional mechanic will be able to do this for you and diagnose the problem with your A/C system accurately.

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