How to Replace AC Compressor: Preparation and Process

A compressor is a vital part of the operation of a car’s air conditioning system. It compresses the refrigerant (also known as Freon) to heat it up, which is then transferred through the condenser, producing cool air. How to replace AC compressor when it does not work anymore? Is it a complicated process demanding the involvement of a professional mechanic? Let’s find out the answers.

Functions of an AC Compressor

A working compressor is essential if you want the car AC to blow cold air. The compressor works like a pump. A belt that is connected to the engine drives this compressor.

This component draws in Freon from the evaporator, compresses the coolant gas, and then sends it through the condenser.

Malfunctioning AC Compressor Symptoms

Before knowing how to replace AC compressor, you should know if it even needs the service. How do you know that the component is giving troubles?

AC compressor
A car AC compressor. (Photo Source: eddytech)

These are the warnings signs to be aware of:

  • AC blowing hot air
  • AC is not cold enough
  • Intermittent cooling
  • Refrigerant is leaking
  • Strong smell of coolant gas
  • Loud noises from the compressor
  • Compressor bearing failure
  • AC system is not turning on

Any of these signs may indicate a problem with the compressor. After diagnosis, if you are completely sure that the said component is malfunctioning, move to the next segment to know how to remove it and install a new one.

How to Replace AC Compressor: Preparation and Process

Replacing the car AC compressor is not super complicated. But you have to have some mechanical knowledge to navigate through the process.

Things to Do Before the Replacement

Before starting the process, you should familiarize yourself with the air conditioning unit and the functions of its various parts. In addition, doing these things will make sure a smooth changing and re-installation process.

Flush the condenser. This will remove debris from this component along with any contaminated compressor oil.

Remove as much contaminated oil as possible. Also, the compressor oil should not have any moisture. The accumulator in the AC unit is responsible for drying off the moisture trapped into the system. It also stores liquids like coolant and compressor oil and filters unwanted particles.

The hose assemblies are the other components that you have to clean. There are three hoses that you have to remove from their connecting parts and then flush to get rid of oil and debris.

Performing a system flush is the best way to clean the AC unit’s internal parts. It will clean off the last traces of all debris and contaminants. However, don’t ever flush the compressor itself.

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How to Replace AC Compressor: The Process

Compressor replacement is an expensive job. The average cost of the whole process, including the price of a new compressor and labor costs could be from $700 to $1,000.

So, before tossing out the old one, have an experienced mechanic look at it to see if a repair is possible. Otherwise, follow these steps to take the old compressor off and install a new one.

Step #1

The first thing you have to do is loosening the belt before removing the lines attached to the compressor. There are some bolts that keep the compressor mounted to the AC system. Remove them too.

Step #2

The next step is to detach the compressor from its slot. Be careful because the attached lines are thin and can be frayed easily. There might be fluids coming out of the lines. Remember to wear gloves because these fluids can hurt the skin.

Step #3

This stage involves taking the preparation for setting up the new compressor inside the air conditioning unit. The new one has to have the same configuration as the old unit. The intake and exhaust sides have refrigerant ports. The dimensions of these ports and the check belt pulley have to be the same.

How to replace AC compressor easily? Taking the mounting bolts from the old component will make the process easier. Add oil to the joints for proper lubrication.

This is the stage where you have to replace the old O rings and install the new ones. These rings seal the high and low side lines to the compressor housing. They wear off over time due to pressure and heat.

How to replace AC compressor
You can do it without professional help. (Photo Source: teamworkgarage)

Step #4

This is the step where you will install the new compressor. Place the compressor onto the engine bay and fasten the mounting bolts to keep it attached to the engine block. Install the refrigerant lines by removing the port dust covers. Fix them with mounting bolts but not too tightly.

After affixing all the bolts, it is time to reconnect the electrical connector to the refrigerant control valve or the engagement coil. Also, re-install the alternator and the serpentine belt.

Lastly, finish the process by mounting all the removed tubes and hoses along with tightening all screws, brackets, and bolts.