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Q: How Long Will the AC Run if My Engine Is Off?

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How long will my AC run if my engine is off?

A: The ability your car has to make cold air f...

The ability your car has to make cold air for your comfort stops when the engine does. The heart of the A/C system is the A/C compressor, whose cycling clutch is driven by a belt connected to your engine’s pulley. If the engine is not turning, the A/C compressor won’t be turning either.

After shutting the engine off, when the A/C has been on, you will notice cool air still coming from the vents if the blower fan remains on. However, you’ll also notice that the temperature of that air soon begins to rise since the refrigeration portion of the system (compressor) has been shut off. An exception to this would be on some hybrid vehicles that have electric motors turning their compressors enabling the A/C to still operate even when the gasoline engine is in idle-stop mode.

If you run into any issue with this system, there are ways to diagnose the automotive air conditioning system by yourself. However, if you feel overwhelmed, reach out to a certified mechanic who will be able to diagnose and fix your A/C.

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