How to Quiet a Noisy Car AC Compressor

A noisy AC compressor can interfere with your peace of mind when you are driving your car.

There are different kinds of noises an AC compressor can make such as buzzing, humming, grinding, whirling noise, etc.

If you are looking for how to quiet a noisy car AC compressor, then these tips will come in handy to help you out.

But before we get into the fixes, let’s first check to see the causes of such noise.

how to quiet a noisy car ac compressor

Causes of Noise in the Car AC Compressor

There are different causes of noise in AC compressors. Here are some of the possible causes of noise in your car’s AC compressor.

1). Dirty Particles in the AC Compressor

If there are dirty particles such as leaves, dust, and other debris present on the surface of the air conditioner. These particles can block the air filters and start producing rattling noises.

2). High Air Pressure in the Air Conditioner

High air pressure can also cause noise in a car AC due to explosions in the compressor anytime the air moves into the air conditioner.

3). Old and Loose Screws

Old screws can unfix themselves and start making loud noises like vibrations and rattling noise. This is because the sudden vibration that the air conditioners make when they are turned on can cause the screws to become loose over time.

4). Free and Loose Air Filters

When the air filters are loose, the air conditioner produces a loud noise when starting because the air passes through the air filters, and if there are some loose parts, the air will pass through these parts, producing some noise.

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5). A Leaking Refrigerant

Leaking refrigerant in the air conditioner allows air to pass in and out of the conditioner contrary to normal operations. The sudden air movement causes some noise when the air conditioner is starting as it lowers the refrigerant level.

6). Faulty Electrical Connectors

Faulty electrical connectors can cause noise because the connectors keep switching off and on. This problem can even cause some sparks when starting the air conditioner where noise accompanies these sparks.

7). Insufficient Lubrication in the Motor

Lubrication of the motor prevents friction and enables fast and easy running. Some AC motors require you to lubricate them regularly and if this doesn’t happen, it will cause the motor to start to produce noise its starts.

How to a Quiet Noisy Car AC Compressor

Here are the unusual noises that your car AC compressor might be making and what you can do about it.

Buzzing Noise

A buzzing sound is a good indicator that your AC compressor may be damaged. This sound usually come off when you turn on the car AC.

Mostly, this is caused by excess or leaky refrigerant. When excess refrigerant also known as Freon is added to the cooling system, it can affect the function of the AC.

Too much refrigerant damages the AC compressor as it collects inside it and can lead to subcooling below normal temperatures.

This can result in damage to the mechanical parts of the compressor. If this is not given the proper attention, it can lead to irreversible damage.

In a case of leaky refrigerant, you will have to investigate and detect the leakage and use a Freon leak repair kit to repair it.

Knocking Sound

A knocking or clicking sound when you start the AC may be a result of the mounting of the compressor part. Typically, the mounting bolts have become loose.

To fix this issue, you will need to start the engine of the car open the hood and observe the cooling system.

Look out for any abnormalities and if you notice loose parts shaking or moving around, then it’s caused by loose mounting bolts.

The problem can be fixed by tightening the bolts using the appropriate wrench tools.

Consistent Rattling Sound

A consistent rattling sound is an indication that the AC compressor is about to damage. This can be due to several factors such as a worn-out belt or the compressor clutch that needs replacement.

In situation, you will need a mechanic to have an overall check of the cooling system to diagnose the real problem.

Constant Vibration & Noise

This may be because your compressor needs lubrication oil. The lack of lubrication is usually caused by leakage or low pressure in the compressor.

To lubricate the compressor, you will need a good oil injector and refrigerant oil.  Start the car and then turn the AC to maximum cooling and inject the oil into the cooling system by following the manual instruction.

Once this is done properly and the car begins running the oil, the sound will disappear.

Loud Shrieking Sound

This is one of the most common sounds many motorists face it comes to problems with their AC compressor.

This sound is usually an indication that something is wrong with the serpentine belt.  The serpentine belt is the belt that runs the compressor. So if it’s experiencing issues, there are several ways to fix it.

Spray the belt down with some water using a spray bottle. It can fix the sound. Otherwise, you can also check the belt for wear and tear. If it’s worn out, replace it.

If after the above, you still hear these sounds, then you will have to take the car to a professional for a proper check-up.

Hissing Sound

In most cases, then sound shouldn’t be a cause for alarm. It is mostly caused by the equalizing pressure due to the refrigerant moving from a high-pressure side in your compressor to a low-pressure side.

This sound is usually persistent even after turning off the car.

This can also be an indication that there is something wrong with the entire cooling system. This can possibly be caused by a leaky refrigerant line, internal valve leak, or high-pressure build-up inside the compressor.

Final Thoughts

The best practice when it comes to car AC is when you notice some unusual sounds coming from it, try and fix it before the damage gets extended.

You can use these above tips to help in diagnosing and fixing the unusual sounds coming from your car’s AC compressor and if the issue is beyond you, then seek a professional mechanic’s help.

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