The Signs of Leaking Around an AC Compressor

by Jen Davis

The air conditioning (AC) compressor in your vehicle provides cool air and power for the air-conditioning system. This small device works by building up pressure as the engine runs and propelling cold air into your car. The AC compressor only contains a small amount of fluid, which acts a lubricant to keep its parts cool and running smoothly during operation. If the fluid leaks out of the AC compressor, you must repair your vehicle's air conditioner.


If the fluid leaks out of your vehicle's AC compressor, you may hear noises and rattling as the compressor runs dry and lacks the lubrication it needs to run smoothly. Some compressors make more noise than others, but pay close attention if your vehicle's air-conditioning system begins making knocking noises or metallic or grinding noises, as these can indicate low coolant and/or a compressor that is about to stop functioning.

Seized Compressor

Both oil and coolant circulate through the AC compressor, so if the fluids leak out, the compressor may seize up and stop working completely. If the compressor seizes up, the air conditioner will no longer cool the car, and you may hear squealing noises from the belts as they attempt to turn the seized-up compressor.

Visible Leaks

Leaks can occur both externally and internally around your AC compressor. External leaks commonly occur around the compressor shaft seal, hoses, O-rings, gaskets, condenser, connectors or evaporator. Examine all these areas thoroughly if you believe your AC compressor is losing fluids. Visible leaks can be hard to detect, so you may need to use a dye or an electronic leak detector to pinpoint the leak's location. You may not be able to detect internal compressor leaks without taking the compressor apart physically.

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