How To Quiet A Noisy Car AC compressor

by Jennifer Porterfield | Last Updated: January 23, 2024
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When it comes to strange noises that a car makes, naturally this is always quite concerning. After all, a healthy car shouldn’t be making any noises you are unsure of.

How To Quiet A Noisy Car AC compressor

In some instances, these noises can be worrying, however, in the majority of cases, there is an easy solution to this problem. 

If you notice that your AC is making a loud noise when it is running or turned on, the chances are that you have an issue with the AC compressor.

This may sound quite confusing if you are unfamiliar with different car parts. However, in the vast majority of cases it can be fixed and made quieter fairly easily.

In this article, we will be chatting you through the causes of a noisy car AC compressor and how you can reduce and rectify this. We hope you will find this article useful.

What Causes A Noisy Car AC Compressor?

When it comes to noisy car AC compressors, this typically causes a buzzing sound. This can be quite annoying, especially if you need to use your AC for an extended period.

The main reason why this buzzing sound is created is likely due to the AC compressor being overcharged. This is something you will want to avoid where possible.

When the AC compressor is overcharged, this is typically caused by the liquid refrigerant that is found within the AC compressor system. In order to prevent this buzzing noise from occurring, you will need to take a closer look at this liquid. 

How To Quiet A Noisy Car AC Compressor

As we have already discussed, the buzzing noise that can be heard within the car AC compressor is typically caused by the liquid refrigerant.

If there is too much of this liquid refrigerant within the AC compressor and unit, it will become overcharged. This causes the unit to not work properly, and as a result the buzzing noise can be heard. 

Replacing The AC Compressor

One of the ways in which you can stop this from occurring is to replace the AC compressor completely. However, given where it is placed within the AC unit, this is not easy to achieve.

In addition to this, it can also be quite costly and expensive to replace. While this may need to be done in some instances, you will always want to avoid replacing it completely where possible. 

Removing The Excess Refrigerant Liquid

The easiest way to quiet a noisy car AC compressor is to remove the excess refrigerant liquid. This is fairly easy to do. However, you can have this done by a professional if you would prefer not to take the AC unit apart. 

Once you have removed the excess liquid, you should notice that the buzzing noise has improved. If it returns, you may need to look into a more permanent solution to this problem. 

Oiling The AC Compressor

In some instances, if the AC is sounding clunky or is rattling, then the compressor may need to be oiled. This will help to lubricate the parts and will help them to move with ease. Again, this is something that is fairly easy to resolve yourself. 

The oil you will need to use will vary depending on the make and model of your car, and the SC unit. It is important to check this before using the oil. Once you have the correct oil, you will want to place it into an oil injector. 

Using an oil injector is the best way to apply the oil, and it is more precise. It allows the oil to be placed on the harder to reach areas of the AC compressor. You do not need to use a lot of oil. 

When applying the oil with the injector, the AC unit needs to be turned on, and the injector is placed into the pipe by the blue valve knob that first needs to be twisted.

Only a small amount of oil should be applied, even if you are tempted to use a larger amount. 

Too much oil can cause damage to the AC compressor, and it can also be dangerous. You will want to avoid the damage caused, as the compressor is expensive to replace.

While this is a fairly easy task to carry out, it can be more difficult if you are not a mechanic, or you are inexperienced with cars. As a result, if you have any issues, it is worth contacting a professional. 

They will then be able to carry out this task for you and suggest any other work that may be done to the AC unit to help lower the noise it creates. 

Replacing Compressor Parts

If the rattling or buzzing continues, you may need certain parts of the AC unit replaced, rather than the whole compressor. Some of the components that may need to be replaced include the serpentine belt, or compressor clutch. 

These are costly, but less expensive to purchase than the whole of the compressor. We would recommend contacting a professional in this instance. 


We hope that you have found this article both reassuring and useful. As you can see, there are a number of different reasons why your AC compressor may be noisy. Even so, all of these issues are fairly easy to resolve and rectify.

As the AC compressor is quite expensive to replace in full, where possible, you will want to look into fixing the issue. By keeping the AC compressor lubricated, and checking for any broken parts, this will help to keep the repair costs down. 

In some instances, you may just need to empty any excess refrigerant liquid that is present. You will always need to ensure that you are using the correct products, such as the oil.

If you use the incorrect products or too much oil, this can cause more damage. 

By following the instructions provided above, the noise levels of the AC compressor should lower significantly. However, if they do not, you may need to speak to a professional about this issue. 

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