Understanding the AC compressor

Would you like to keep cool during the summer and have a clear window in the winter? Well, you’ll need an AC compressor that is working properly. The air conditioning (A/C) system in your car is made up of different components, but one of the critical parts that creates the system’s necessary cycle is the compressor.

AC compressor

Your entire A/C system won’t be able to produce cool air for the car’s interior without AC compressor. Its main function is to provide the proper amount of pressure to the refrigerant in the car in order to activate its heat-transfer characteristics and change temperatures. By doing this, you can keep cool during the summer and have a clear window in the winter.

Well, today we will be looking at the definition, function, symptoms, location, and replacement cost of the AC compressor. We will also be looking at the frequently asked questions about the air conditioning compressor.


What is the AC compressor?

The AC compressor is the most critical part of the air-conditioning system. It is the power unit of the air-conditioning system that puts the refrigerant under high pressure before it pumps it into the condenser, where it changes from a gas to a liquid.

An engine accessory belt powers the A/C compressors on the majority of automobiles. The compressor won’t run as effectively if the belt is old and slips. Refrigerant leaks from compressors can also reduce the amount of cold air that enters the interior.

There may not be any chilly air if internal components malfunction. Not all a/c issues are caused by low refrigerant levels in the system. Some are brought on by problems with components of the system, like the compressor.

How the AC compressor functions

The compressor for your car’s air conditioning is actually one of the system’s main components, which means that without the AC compressor, the air conditioning system cannot function.

Essentially, it’s a mini compressor that is often driven by the auxiliary drive belt. The pulley on your A/C compressor receives power from your crankshaft as your engine turns over through the auxiliary drive belt.

However, your air conditioner’s compressor has a clutch installed in the pulley because not everyone uses their air conditioner completely when driving.


When you turn on and off your air conditioning, the compressor will be engaged and disengaged by this clutch. Therefore, if your air conditioner is turned off, the compressor’s pulley will turn, but the compressor’s internal parts won’t.

The air conditioner compressor is made to increase the temperature and pressure of the refrigerant inside the system when cooling.

When the gas-based refrigerant reaches the condenser in your car, the heat it has absorbed from the evaporator may be released because of the way the molecules are packed tightly.

Symptoms of a bad and failing AC compressor

Below are six symptoms of a bad or failing AC compressor:

  • AC system blows moderate/hot air.
  • The compressor clutch is not moving.
  • Unusual noise from the AC compressor.
  • Refrigerant Leak.
  • Excessive Wearing on the Auxiliary Drive Belt.
  • Smell of burning rubber.

AC system blows moderate/hot air

When you turn the AC cooling level to maximum, the most common sign of a bad and failing AC compressor is that you do not notice a change in temperature or that the temperature rises.

If your car indicates that your A/C is on but you don’t feel a temperature change, the compressor may be malfunctioning. This is typically indicated by a tiny light on the A/C button. Checking your A/C compressor’s power feed is a good way to see if the problem is with your compressor.

The outside of the body of the compressor is usually where the 2-pin connector is located. You ought to have a live feed going to the pump while the car is running and the air conditioning is turned on. If your compressor has the proper feeds but isn’t functioning, it may be a broken A/C compressor.

The compressor clutch is not moving

The majority of AC compressor pulleys are made of two components. The engine will always spin the inner pulley without rotating the axle into the compressor. This pulley also includes an outside clutch that engages when the AC compressor turns on.

This clutch won’t engage and turn the compressor axle if it has failed. It must be properly diagnosed because the compressor may also experience this if there is no electrical power. But rather than a bad AC compressor, this is more of an indication of a bad AC compressor clutch. However, you frequently need to replace the compressor if the AC compressor clutch is damaged.

Unusual noise from the AC compressor

When the compressor clutch is engaged, the pump’s internals have to work extremely hard to keep up with demand. You’ll typically start to hear a grinding noise coming from the engine after the bearings and other metallic components inside the compressor start to wear and become noisy.

Try turning your air conditioner on and off and listening for any change in the grinding noise to see if your compressor is the cause of the noise. The internal parts of your compressor may have worn out and need to be changed if you find that the noise goes away when the pump is turned off.

Refrigerant Leak

The air conditioning system in your car has sensors that measure how much refrigerant is in the pipework. Your lower pressure switch will detect a leak on one of these pipes in your car and turn off the compressor to avoid damage from the refrigerant running out.

Due to the components being difficult to reach, it can frequently be challenging to locate a refrigerant leak on a vehicle. But if you’re looking for a leak, the compressor body itself is a fine place to start.

If the compressor has started overcompressing the refrigerant because of an internal problem, this might result in an excessive buildup of heat and pressure inside the compressor’s body, which can lead to the seals bursting. causing your air conditioner to stop working by leaking its refrigerant.

Excessive Wearing on the Auxiliary Drive Belt

Checking your A/C compressor’s pulley could be helpful if you have had to replace your auxiliary drive belt and have observed that your new one is wearing out quickly or creating a screeching noise.

The pulley on your compressor may develop excessive bearing movement as it ages and run at different angles due to the pulley’s bearings. This movement usually results in the snatching and grabbing of the rubber auxiliary drive belt, which speeds up the belt’s early wear. Or the excessive movement may cause the rubber belt to rub against the misaligned pulley, causing a high-pitched screech.

Smell of burning rubber

When you turn on the AC and smell burning rubber coming from the engine bay, the AC compressor may be seized and the serpentine belt may not spin on the compressor pulley.

However, if you have been observing it for a while, there is probably something else wrong with your car. This will make the serpentine belt snap off quite quickly.

AC compressor location in the vehicle

The AC compressor is usually found on the auxiliary drive belt with other belt-driven accessories.


It will be powered by an electrical plug and have two refrigerant pipes attached to the body of the device.

You may look underneath your car to see the compressor because it is mainly found near the bottom of the engine, underneath the alternator and power steering pump.

AC compressor location

AC compressor replacement cost

It can be expensive to purchase a new AC compressor because it is a pretty complex component. Depending on the car model and labor costs, the average cost to replace an AC compressor ranges from $400 to $1200. While labor costs $200 to $500, an AC compressor ranges in cost from $200 to $700.

However, the AC system needs to be refilled after the compressor is replaced, which costs between $100 and $200. You must first conduct a leak test on the AC system before refilling it. This can take a while, and the labor involved will be expensive.


How does the AC compressor work in a car?

The engine of your vehicle uses a belt to drive the compressor for the air conditioning system. It moves the refrigerant into the system to drive the compressor for the air conditioning system. It moves the refrigerant into the system. The refrigerant is then compressed to raise the temperature after being sucked in as a low-pressure gas.

How do I know my car’s AC compressor is bad?

  • AC system blows moderate/hot air
  • The compressor clutch is not moving
  • Unusual noise from the AC compressor
  • Refrigerant Leak

How does a car’s AC compressor get damaged?

If the refrigerant lines in your system develop holes or cracks, the air conditioner will leak refrigerant. After some time, the level drops so low that the compressor will have to work harder to push through the system enough refrigerant to cool your room. The compressor may eventually fail due to the strain.

Will a broken AC compressor affect the engine?

It is definitely a problem when your A/C compressor breaks and it can affect your car as a whole. Your car’s engine may suffer if you drive with a damaged A/C compressor. Keep in mind that everything in your car is interconnected. The engine powers vital components of your car’s air conditioning compressor, such as the pulleys and belts.

Can a car’s AC compressor be repaired?

AC compressors can sometimes be repaired. However, it is always better to get a new compressor and replace the damaged one. It will most frequently lead to a better, longer-lasting repair in addition to being the most time-efficient solution to the issue.

How long does a car’s AC compressor last?

The lifetime of a car’s compressor is normally 12 to 15 years, depending on how well the car is maintained. To avoid a premature failure of your vehicle, it is crucial that you routinely check and service it.

What happens if I don’t replace the AC compressor in my car?

As long as you don’t want or need air conditioning in your vehicle, you will be fine. Your AC pulley is a clutch-equipped free-spinning pulley. Until the air conditioning is turned on, it will spin at will. Even if the clutch isn’t functioning properly, you can still drive your vehicle.

How much does it cost to replace an AC compressor in a car?

The typical price to replace a car’s air conditioning compressor is around $1,100. Depending on where you live, labor and part costs can differ significantly. The parts can cost between $650 and $840, while the labor can cost anywhere between $160 and $200 on average.

What causes AC compressor failure?

Some of the common reasons for air conditioner compressor failure include power surges, overheating compressors, and dirty AC coils.

When replacing the car’s AC compressor, what else should be replaced?

You will at the very least need to replace the receiver dryer, expansion valve, compressor assembly, and clutch for the seized compressor. You will also need to flush the system. To fix your air conditioner, I suggest having a professional check your car to determine whether any other parts need to be replaced.

What do you need when replacing an AC compressor?

Below are the items you’ll need when replacing an air conditioning compressor.

  • New compressor.
  • Refrigerant recovery tank.
  • Refrigerant.
  • Equipment to recover and charge system.
  • Torch.
  • Basic hand tools such as wrenches, screwdrivers, ratchets, and pliers.


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In conclusion, the air conditioning compressor is essential for keeping a cozy and regulated interior climate in a variety of applications, including those for homes, cars, businesses, and industrial processes. This essential part is in charge of compressing and moving refrigerant, allowing heat to be transferred and ultimately chilling the area. An AC compressor needs to be properly maintained and cared for in order to function effectively for a long time. The effectiveness and environmental impact of these devices keep improving thanks to technological advancements, which makes them a crucial component of contemporary comfort and temperature control systems.

That is all for this article, where we discussed the definition, function, symptoms, location, and replacement cost of the AC compressor. We also looked at the frequently asked questions about the air conditioning compressor.

I hope you gained a lot from the reading. If you do, kindly share it with other technical students. Thanks for reading, see you around!