Replacing a broken air conditioning compressor in your car shouldn't be a major hassle.

The cost will vary depending on whether the existing air conditioning compressor unit can be repaired or if you need a new AC compressor altogether. The average AC compressor replacement cost for parts and labour runs around $500-$750 per vehicle.

What does an air conditioner compressor do?

The air conditioning system in your car is made up of several parts. The compressor is the most important part of the car's AC system. When you turn on your AC to get cool air, the compressor pumps refrigerant through a tiny valve called an orifice tube. The orifice tube directs hot and cold airflow to maintain constant cool temperatures, especially on a hot summer day. If your AC is blowing warm air, it could be because there isn't enough refrigerant in the system, or you have a failed compressor.

In humid weather, the car air conditioning demister unit draws moisture from the vehicle's interior, maintaining clear windows.

Symptoms that indicate replacement may be needed

If you notice any of these symptoms while using your AC, then you need to have the car's air conditioning system diagnosed by a certified mechanic as soon as possible.

  • AC blows cool before reaching normal operating temperature, then starts blowing warm air.

  • AC is struggling to reach normal operating temperature when the car is moving.

  • Cool air is only blowing at the defroster.

  • AC doesn't blow cold if the car has been running for a few minutes.

  • Weak, inadequate, or low-pressure cool airflow from vents during driving.

  • The noise level in the cabin of your vehicle sounds unusually loud.

In some cases, the air conditioning unit could be blowing hot air for reasons other than a faulty compressor. For example, a broken serpentine belt or a leaking vapour tube are some of the reasons the car air conditioning may not be cooling your interior.

Consult a certified technician in case you are not sure what could be causing the problem. The correct diagnosis will give you an accurate estimate of the problem. It will also save you needless repairs and unnecessary AC compressor costs.

What causes an AC compressor to stop working?

Many things could contribute to the AC compressor failing. These include, but are not limited to:

Low refrigerant levels

The cooling system may be low on refrigerant if the line that feeds the system is loose or if there's a leak in one of the hoses or fittings. This will cause insufficient cooling.

Bad fan clutch

If your vehicle has an electric fan, it should spin at high speeds while you're driving and at low speeds while idling. A bad fan clutch can cause this to happen improperly, resulting in poor airflow through your vents.

Weak engine

AC compressors require adequate power from the engine for the proper operation of the compressor's moving components. You may notice that it doesn't work properly if your engine isn't up to snuff.

AC hose failures

Several components in the AC system are connected by tubing or hoses. If they become worn or brittle, it can cause the entire system to fail. However, worn or broken vapour tubes are minor repairs costs compared to a full AC compressor replacement.

How much does it cost to replace a car air conditioner compressor?

Several additional factors can cause the car AC compressor cost to vary widely.

Aftermarket vs OEM

If you're buying parts or the replacement AC compressor from the dealer, they will be more expensive than aftermarket components. A new OEM AC compressor will cost around $500-$750, whereas a remanufactured or reconditioned one (which is functionally identical to an OEM one) will typically run between $250 and $400.

Location of AC compressor

Where the AC compressor is located in your car can affect the price. Many cars have multiple air conditioning lines routed through the engine bay, and some engines may not have enough room for all of these lines and an AC compressor. If you're looking at a vehicle with this design, expect to pay a higher labour cost because of the intensity of the compressor replacement work.

What other repairs should I expect after replacing my car's AC compressor?

After you get your car back from a mechanic, there are several other parts that may fail soon afterward if they weren't replaced at the same time as the broken AC compressor. These things include, but aren't limited to:

AC orifice tube

This is that little metal pipe that directs the flow of refrigerant into the ducts that distribute cold air to the cabin. It can get dirty over time or become corroded by leaks. If you don't change it while replacing your AC compressor, then it will likely leak shortly afterwards and need replacement.

Expansion valve

Like the orifice tube, this part can get fouled up with debris over time. Expect to pay around $100 for a new one if you need to replace yours.

Drier

Also called an accumulator, this part collects moisture from the gas in your system before it goes through your evaporator coil (the thing inside your car's dashboard that makes cold air). When it's time to replace this, you should also have the evaporator coil replaced. Fortunately, it won't break the bank - these can be bought for just a few hundred dollars.

Evaporator core

This is the most expensive thing on your car that you'll likely need to change if they stop working properly. If your evaporator core goes bad, then you'll probably spend between $500 and $2000 having it replaced depending on which vehicle you drive, how much work is involved in getting at it, etc.

How long does it take to replace an AC compressor?

It typically takes around 4-8 hours of labour to replace an AC compressor on a vehicle. The two main reasons for this long time are the number of components involved and the tight working space. These issues aren't unique to air conditioning compressors. A major compressor repair job may take several hours because it is complicated, and there's not much room to work with in most engine bays, unlike fixing the air conditioner in your home.

Can I replace an AC compressor myself?

If you're not mechanically inclined or do not have access to the right tools, it is best that this kind of repair is performed by a licensed mechanic. The work involved isn't trivial as toxic refrigerant needs to be removed before removing the old compressor. After getting the new one in place, you'll need to evacuate and recharge your AC system using the right equipment. If something goes wrong during any of these steps, there's a risk of serious injury from inhalation of refrigerant gas or exposure to high-voltage sparks. Again, it is best to leave this work to a professional mechanic.

How does a car AC compressor work?

The AC compressor is attached to the engine of your car and draws power from it using a serpentine belt. As the engine spins, so does the compressor, which compresses the gas refrigerant. The compressor also contains an electric motor that is responsible for spinning the compressor when it needs to.

The gas is compressed by the rotating parts in the compressor, which increases its pressure and temperature. The hot, high-pressure refrigerant then flows through a heat exchanger inside the car's condenser unit before entering the evaporator coil. As you can guess, this process makes cold air inside your car's cabin as cool air passes through the dash vents.

The QLD Governmnet has more information on refrigeration and airconditioning gasses.