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Signs your car needs a new AC

Signs Your Car Needs a New AC Compressor

There’s nothing worse than getting into a car with no air conditioning on a hot summer day. When your AC system is no longer cooling efficiently, it could be due to a bad compressor. Check out these tips from My Auto Store to make sure you don’t get stranded in the heat without A/C!

How do you know if your car’s AC compressor is bad?

Vehicle air conditioning systems rely on the compressor to circulate refrigerant through the system. If your compressor breaks, the refrigerant can’t do its job of cooling the hot air, resulting in an uncomfortable ride.

There are a few signs that your air conditioning is failing because the compressor is broken. The most common signs 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 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.


Squealing – A squealing noise coming 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 large squeals. Replacing the 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-out pistons or bearings. Grinding noises when you turn on the air conditioning are a tell-tale sign you will be replacing your 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 knocking noise. Your air conditioning may still work despite the knocking, but sooner or later the damage 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. 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.

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.

What causes a vehicle’s A/C compressor to go bad?

Most A/C compressors fail after years of normal wear and tear, especially in hot climates where the system is being used more often. Overheating can also be an issue if the unit is running without ventilation under the hood. As a rule of thumb, the average lifespan of a vehicle air conditioner is about ten years.

Diagram of an air conditioner from My Auto Store

Should I fix my car with a used AC compressor?

Depending on which component is broken, you may be able to have a repair shop fix the A/C compressor. However, between the cost of parts and labor, it is often less expensive to replace the entire unit.

My Auto Store Diagram of AC Compressor

How much does a used A/C compressor cost?

Replacement costs of an AC compressor depend on the type of compressor, labor costs, and whether you buy a used or new unit. Brand new A/C compressors cost about $500 or more, but you can get a high-quality used AC compressor for much less. Many cars that have been totaled in accidents have perfectly good compressors. Depending on your make and model, replacing it with a used compressor will run you about $60 to $300 plus the cost of labor.

CostLaborTotal Cost
New A/C Compressor$500+$300$800+
Used A/C Compressor$150+$300$450+

What is the best place to buy a used AC compressor near me?

You can find all kinds of used auto parts, including A/C compressors, at My Auto Store. Browse thousands of quality A/C compressors, engines, transmissions, and more- all quality-inspected to ensure they will keep your car running for years to come. Stay cool!

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