How to Replace Air Conditioner Compressor?

A compressor is a part of an air conditioning that is responsible for supplying the cool air. It is always good to know “how to replace air conditioner compressor” as you may feel the need to change it anytime. Or if you already have a bad compressor at the time, then this guide is going to help you with the same. 

How To Replace Air Conditioner Compressor: Make Your AC Work

The compressor compresses the refrigerant into a high-pressure gas to transfer it further. Without proper compression, the gas won’t be able to travel further, and the system won’t absorb any heat from your car’s cabin.

Let’s get started with the replacement process; we will try to keep it as simple as possible-

Taking the Compressor off the System

Get to your car’s battery and take off the negative terminal, so you don’t get any short circuit. Now, to get to the serpentine belt, remove any covering and access your engine. Have a look at all the tubes or hoses and remove them too; the process of “how to replace air conditioner compressor.”

There may be other accessories or parts, and you can see the compressor beneath them. Take off all these accessories by using the right wrenches and take off the bolts and wiring.

Tip: When you replace ac compressor, keep all the bolts and parts that you remove in a safe place.

You would find an electrical connector too near the compressor. Using the screwdriver, you can unbolt this connector easily. Locate the high and low side refrigerant line and loosen the bolts there too.

You need to grip this line and slightly twist while pulling it upward and disconnect. You should remove both high and low side fittings at this point.

Take off all the accessories or parts
Remove the car battery carefully and the negative terminal too (Photo Source: diy-time)

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Once you are done with the mentioned parts, it is time to get to the lower and upper mounting bolts and using a universal joint socket or small wrench, perform the removal.

Now, you may see that last mounting bolt before you can grasp the compressor and take it off the vehicle. You may also need to hold the compressor while removing that last bolt; do it carefully without hurting the unit or yourself.

Inspecting the Removed Compressor

It is wise to check the old compressor unit before just throwing it away. This way, you can determine the issue or what made it fail. If by turning the clutch, you can hear a grinding sound, it means the system contains foreign metal debris that needs to be flushed out.

Get an AC system flush kit from any local or reliable store and unblock the expansion valve or orifice tube. Check the refrigerant lines and exhaust ports for any metal and clean them too.

If the expansion valve seems to be completely blocked, it is best to replace the same.

Getting To the New Compressor

For the car ac compressor replacement, get a new compressor unit. It can vary in design if it is an upgraded version, but the universal installation process remains the same.

One thing you need to be sure about is the intake and exhaust sides of the refrigerant ports. Check the belt pulley as well for the number of ribs along with the outside diameter. Use the mounting bolts from the old unit and transfer them to the new one.

Adding compressor oil to the unit is important too. As some unit comes with pre-added oil, always check the user guide of the unit and determine if you need to fill oil or not.

If the expansion valve seems to be completely blocked, it is best to replace the same
Always check the old compressor unit before just throwing it away (Photo Source: gobdp)

Replacing the Old O Rings

Those high and low side lines use the O rings to create a sealed environment to keep against the leaks. For the auto ac compressor replacement, you should replace the O rings as well to ensure that no future leaks take place. Learn replacing radiator hose and several other parts of your car here Maintenance Tips.

Get to both high and low side lines and take off the O rings carefully. Get your new O rings, and they should match the old ones exactly for the diameter and the length as well. You think about keeping with the old O rings, but in most cases, it is not a good idea to do so.

Take the O rings and carefully slide them on the side lines. Once they sit securely there, apply some peg oil over the O rings to get the installation done.

Lastly, Installing the New Compressor

Clear the path where you are going to place the new compressor. Use your hands to place the mounting bolts into the unit and later secure the unit with a wrench or socket.

Get to the high and low side refrigerant and install both lines; make sure the bolts are tightened. Put everything back in order, such as the electrical connector and any accessories that you removed.

Once they sit securely there, apply some peg oil over the O rings to get the installation done
Get to both high and low side lines and take off the O rings carefully (Photo Source: pakwheels)


Note down all the things and their position in a notebook or take pictures for reference. Do clean the entire AC system before placing the new unit, and this is “how to replace air conditioner compressor.”