How to Quiet a Noisy Car AC Compressor

How to Quiet a Noisy Car AC Compressor

A noisy car ac compressor can be a nuisance to a driver. It can make all the occupants in your car irritated and make it difficult to engage in a conversation. They can also be a hazard if not taken care of. 

The good thing is that there are actions that a driver can take to stop the noise. In the following blog, we will discuss causes and tips on how to quiet a noisy car ac compressor.

How to Quiet a Noisy Car AC Compressor

There are two types of noise that are emitted from the ac compressor: rubbing or rattling noises and high-pitched whining noises.

Here we will give you some tips on how to fix these two types of noise emitted by the ac compressor.

1. Rubbing or Rattling

ac compressor noise at idle

If there is a rubbing noise coming from the ac compressor, most likely something is vibrating against it.

This can be caused by a belt, hose, or fan; and it’s usually easy to fix. Make sure that no objects are hitting the compressor and make sure all belts and hoses are properly connected.

Another cause of a small rattling noise is small amount of oil on the compressor’s shaft.

You can add a small amount of oil to it by unscrewing the drain plug at the bottom of the compressor and adding a few drops of oil.

If the compressor is making a lot of noise, then it might be bad. In that case, you’ll have to replace it. 

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2. High-pitched whining

ac compressor whining noise

When an AC system makes a high-pitched whining sound, it usually means that the bearings in one of your compartments have gone bad and need replacement.

The serpentine belt is wearing down, it can produce a high-pitched whining noise. This noise is a sign that the belt is about to break.

If you notice a high-pitched whining noise coming from your vehicle’s power-delivery system, get the belt checked out by your local garage.

A broken belt can be dangerous to your car’s engine, so it’s important to replace it ASAP.

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a) Car AC makes noise when turned on

You may hear a hissing or chirping noise when you turn on the air conditioner in your car. This is typically normal and occurs because of various reasons.

First, if you’ve recently purchased a new car, you may hear a hissing noise when you turn on the air conditioner. 

This is because your car’s air conditioning unit is new and has yet to be broken in. As a result, the seals and hoses that connect to the air conditioning unit and the car’s engine may not be tight enough. 

However, if that’s not the case, check the fan belt and make sure that it is not broken. A broken fan belt will obviously cause noise – and you can check and see if the fan belt is loose. 

Also, clean the A/C belt and see if it is catching on something. Check the belts and the hoses and make sure that they are not damaged.

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b) Car air conditioner making a loud humming noise

ac compressor in car making noise

Some car air conditioners may make a loud humming noise. If the noise is coming from the front of the vehicle, it will probably be due to a faulty bearing.

In this case, it will need to be replaced by a manufacturer-approved part before proceeding with any repairs.

c) AC compressor noise at idle

The noise an AC compressor makes at idle is the sound of the motor and fan operating.

It is usually a whirring type of noise, but if you start to hear other noises like buzzing or rattling, it would be time to call for professional AC repair services.

d) AC compressor grinding noise

car makes noise when ac is on

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The compressor is an essential part of the air conditioner that compresses the refrigerant gas into a liquid form. When the refrigerant leaves the compressor it will create noise. 

The grinding sound is usually caused by loose debris in the system, which may be as a result of vibration, wear and tear, or blockages in the system.

There are three main reasons why your AC may be making this noise:

  • An obstruction in the condenser coil
  • A loose fan blade
  • A damaged fan blade

e) AC compressor whines when accelerating

Ac compressor whines when accelerating, this is due to rapid changes in the pressure of the refrigerant. The compressor vibrates, which creates a sound that you hear as a whine.

This noise can be caused by three different things:

  • A faulty bearing in the compressor
  • A worn-out serpentine belt
  • The refrigerant itself becoming contaminated with dirt or water vapor

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f) Car AC compressor rattling noise

ac compressor whines when accelerating

When the air conditioner in the car rattles, it could be a sign of a major problem. It could be a sign that the compressor is damaged or that a belt is loose.

A failed tensioner can also cause rattling noise from your car’s air conditioning compressor. 

If the tensioner fails, the compressor belt will no longer be tight enough to stay on the pulley, so it will rattle.

Another cause of ratting noise is bearing failure in the compressor. If they are not properly maintained, they can fail.

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FAQs on Noisy Car AC Compressor

car ac making rattling noise

What sound does a bad AC compressor make?

The user will hear a clicking or rattling sound coming from the AC compressor. This can be caused by a leak in the refrigerant and the system is not getting enough cooling. Some signs of a bad AC compressor are loud, irregular, and continuous noises coming from the unit.

What are the signs of a bad AC compressor?

-Noise from the compressor.
-The AC system will not cool even though the fan is running.
-The compressor will be warm or hot to touch.
-Noise from the AC compressor that changes with engine speed.

Can you drive with a bad AC compressor?

The answer is, it depends. If the compressor is only slightly damaged (i.e. a leak in the compressor) and you can still hear the compressor running, you may be able to continue to drive the car. 

If the compressor is completely seized, then you likely will not be able to drive the car (at least not without extreme difficulty).

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A noisy air conditioning compressor will make a loud, whirring noise that can be annoying and distracting. There are two steps to quiet a noisy car AC compressor. 

First, you want to ensure that the noise is caused by the AC compressor. If there is a loud rattling noise, it could be caused by loose parts in the engine. If you hear a rattle, then take your car to a mechanic to check it out. 

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