Skip the auto shop - Our mechanics make house calls

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

asked by on

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

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.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. How Long Will the AC Run if My Engine Is Off?

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Ac not cold

Quite often, issues with maintaining cold air flow with an air conditioner are due to a commonly overlooked issue - charging AC refrigerant. Although most vehicles (like your Toyota 4-Runner) have a closed-loop AC, when a leak occurs and...

Q: Can I try using blue devil head gasket repair even if I'm not even sure that the head gasket is the problem?

You can try the Blue Devil head gasket repair fluid. The only thing is if the cylinder head has a crack, the gasket repair will not effect aluminum or cast iron. For the conditions that your described, either the Idle...

Q: AC Fan not running

First of all, check all the fuses to see if any are blown. This way, you ensure all the fuses are good and another system is not causing the problem. You will need to have the fan control module or...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...