Here are 6 Signs Your AC Compressor is Not Working Well (& the Replacement Cost).

It is important to maintain a working A/C in your car if you reside in a warm country.

Unfortunately, there are many parts to the AC system, and it is possible that one or more of them will fail.

If your AC isn't blowing cold anymore, how can you determine if it is the AC compressor? Let’s find out! Let’s begin with a quick look at the signs:

A bad AC compressor can lead to high or unstable air-conditioning temperatures. Open the hood to hear the compressor making noises. Sometimes, there may be refrigerant leaking around the compressor.

This is a detailed listing of some of the signs that an AC compressor may be faulty.

Low AC Compressor Performance

1. The A/C System blows warm air

Although this may sound obvious, it is not the best. If your A/C suddenly stops working, you should be looking for signs such as a bad compressor. 

If your vehicle indicates that your A/C should be on (usually by a little light on the A/C button), but you don’t feel a temperature change, this could point towards a faulty compressor. 

A good way to check if your compressor is the fault here is to check your A/C compressor’s power feed. A 2-pin connector will be located on the compressor's exterior. You should see a live feed from the pump as soon as the engine is turned on and the car is moving. 

If your compressor has the correct feeds to it but still isn’t working, this would suggest a faulty A/C compressor. 

2. AC Compressors Can Make Noise 

As you can imagine, when the compressor’s clutch is engaged, the internals of the pump are working incredibly hard to keep up with the demand. 

When the metal components and bearings wear out, the compressor will make a loud grinding sound. 

A good way to determine if it’s your compressor that’s making this noise is to try switching your A/C on and off and listen out for any changes in the grinding noise. 

If you notice that the noise disappears when the pump is switched off, this would indicate that your compressor’s internals has worn and will require the unit to be replaced. 

3. It isn't moving when the Compressor Clutch moves

Most ac compressors’ pulleys consist of two parts. Without turning the compressor's axle, the inner pulley spins with the engine at all times. The pulley has an outer clutch, which engages when the AC compressor should be started.

The compressor will stop turning if the clutch is damaged. This can be caused by no electrical power, and it should also be properly diagnosed.

It is usually a sign that your ac compressor has a problem clutch, rather than the compressor itself. You may need to replace your compressor if the clutch on the ac conditioner is failing.

The majority of newer cars use variable AC compressors. They spin constantly and lack a clutch.

4. The engine bay emits a burning rubber smell

A burning rubber smell can be detected in your engine bay when the AC is turned on. It could indicate that the AC compressor may have seized.

The serpentine belt will snap easily, but if it has been bothering you for some time, then there may be something else.

5. Over-wearing of the Auxiliary Drive Belt 

If you’ve had to replace your auxiliary drive belt recently, and have noticed that your new one has started to wear out quite quickly, or is making a squealing noise, then it may be worth checking your A/C compressor’s pulley. 

As your compressor’s pulley begins to wear out, it can develop excessive movement in its bearings that cause the pulley to run at varying angles. It can cause excessive movement in the bearings, which will cause pulley to run at different angles. This excessive movement may also cause a loud squeal when the rubber belt rubs against an unaligned pulley. 

If you are unsure if the problem is your fault, take the auxiliary belt out of the compressor. Then check for excessive play in the pulley. Sometimes compressors permit their pulleys be replaced without having to replace the entire unit. This is not always the case. 

6. Refrigerant Leak 

Your vehicle’s A/C system has sensors in place to determine how much refrigerant there is within the pipework. The lower pressure switch in your A/C will notify you if your compressor is running low. 

A refrigerant leak on a vehicle can often be difficult to find due to the inaccessibility of the components that you’re trying to assess. However, a good place to start if you’re looking for a leak is the compressor body itself. 

If the compressor has begun to over compress the refrigerant due to a fault internally, this can cause excessive heat and pressure to build up within the compressor’s body and can cause its seals to burst. This will cause your air conditioner to quit working and release its refrigerant. 

An AC Compressor's Function

Your vehicle’s Air Conditioning compressor is really the beating heart of your vehicle’s A/C system. It’s basically a mini compressor that’s usually driven by your auxiliary drive belt. As your engine turns over, your auxiliary drive belt takes up power from your crankshaft and outputs this to your A/C compressor’s pulley. 

Now, because not everyone runs their A/C 100% of the time they’re driving, your A/C compressor has a clutch fitted in the pulley. As you change your air conditioning off and on, the clutch engages or disengages the compressor. The compressor pulley spins when the A/C switch is off. 

When cooling, the A/C compressor is designed to increase the refrigerant’s pressure and temperature within the system. By tightly packing the gas-based refrigerant molecules allow the heat that the refrigerant has picked up from your evaporator to be released as it reaches your vehicle’s condenser. 

AC Compressor Installation 

Your compressor for A/C will be found on the auxiliary drive belt. The compressor will be equipped with 2 refrigerant pipes and an electric plug.

You will find the AC compressors at the bottom of your engine. They are located below the alternator and power steering pumps.

AC Compressor Replacement Cost

The cost of replacing an AC compressor is typically between $400-$1200 depending on its make and model. A compressor AC costs between $200 and $700, while labor can cost $200 to $500.

Because the AC compressor is such a complicated component, it may be costly to purchase a brand new unit.

It is common for the compressor to be replaced by labor, which can easily run into the $100 range depending on what car you have.

After the AC compressor has been replaced, it is necessary to refill the AC system. The cost of this process can range from $100-200. You will also need to perform a leak test before refilling your AC system. This can be time-consuming and increase labor costs.

Find out more about how much an AC recharge costs.

The price to replace an A/C compressor can vary depending on whether it's easy to access, how much refrigerant you use and what compressor type is used.