Q: Coolant reservoir overflows while air conditioning is running

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Car doesn't overheat but my coolant reservoir tank overflows while I have my a/c running. Why is this happening?

My car has 55000 miles.
My car has an automatic transmission.

Hello, A few different items can cause the coolant reservoir to overflow. If this is going on while the vehicle is not overheating, it is a bit less common.

The most likely causes would be a failure of one of these components:

When the AC is on, it puts a slight strain on the vehicle, which takes up some of the available horsepower.

A qualified Technician such as one from YourMechanic will be able to diagnose your coolant reservoir tank overflow fault and perform any repairs required.

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