How Do You Know if Your Car AC Compressor is Bad?

Vehicle air conditioning systems rely on a few components like the car's HVAC blower and the AC compressor to keep your vehicle cool on the inside. When the blower breaks there is no air blowing through your vents, hot or cold. When the compressor breaks it doesn't circulate refrigerant through the system. Your blower does blow air but it's not going to cool your car, resulting in an uncomfortable ride.

There are a few signs that your air conditioning is failing because the compressor is broken. The most common symptoms of a bad AC compressor are:

1. The air conditioner is blowing hot air instead of cold air.
2. The A/C compressor is making a noise under the hood (squealing, grinding, or knocking)
3. The AC is leaking fluid onto the ground.

HOT AIR

If the air conditioner is blowing hot air, there is a good chance that your car or truck's A/C compressor is low on refrigerant (the liquid inside the system that cools the air). Adding more refrigerant will get your air conditioning to blow cool air again, but if the compressor is broken, it will need to be repaired before you recharge the refrigerant.

NOISES

Squealing – A squealing noise from the car’s air conditioning compressor is a sure sign you need to get your A/C checked out. Squealing noises are usually caused by a worn serpentine belt. When a belt gets worn or warped, it sits unevenly on the pulley and causes loud squealing. Replacing the A/C component belt usually solves the problem.

Grinding – Grinding noises under the hood could be coming from problems with internal parts of the A/C compressor, usually worn or bad pistons or bearings, depending on the type of A/C Compressor your vehicle has. Grinding noises when you turn on the air conditioning are a tell-tale sign you will be replacing your A/C compressor soon.

Knocking – All A/C compressors have a fan, and when that fan comes loose, it can bang into other metal components causing a loud ticking, banging, or knocking noise. Your air conditioning may still work despite the knocking, but sooner or later the damaged A/C blower fan will require a replacement.

LEAKING FLUID

All air conditioner compressors contain refrigerant, which is a liquid that cools the surrounding air to bring down the temperature inside the vehicle when the air is blown through the vents by the blower fan. This chemical fluid is also known as Freon.

If you notice a greasy spot under your car coming from under the hood, it could be your A/C compressor leaking refrigerant. You may have a damaged or faulty A/C compressor or may need to replace refrigerant hoses and lines.

Pro Tip: It’s common for air conditioners to drip condensation onto the ground leaving a wet spot underneath your car. This is completely normal.