How To Quiet a Noisy Car AC Compressor?

A car AC compressor is your saving grace on hot summer days when you need to go out on a drive or run errands.

Having a car AC compressor malfunction or not working correctly causes a significant amount of grievance, which can turn into a really costly issue if not looked into promptly.

How To Quiet a Noisy Car AC Compressor?

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You can quiet a noisy car AC compressor by determining the type of sound the compressor emits. A shrieking/squeaking sound would only require a few drops of water to the serpentine belt. In contrast, a buzzing sound may require a mechanic’s attention. 

Quiet a Noisy Car AC Compressor

This article will discuss the four most common car AC compressor sounds and how to resolve these issues.

Each sound entails a different solution and level of expertise required to fix the problem. Let’s start with the most common sounds car AC compressors make. 

Also read: Do AC Compressor Blankets Work for Noise Reduction?

1. How To Quiet a Squeaking Noise?

When you hear a squeaking noise from under the hood of your car, it can be pretty frustrating to drive around with that type of racket.

There are several ways to diagnose the source of the sound and fix it before anything breaks down. The reasons below will give you a better idea of the source of the problem. 

Pulley Misalignment

There are numerous pulleys that the belt drives, for instance, alternator, idler, and tensioner pulleys. These are being rotated by the belt, and a slight misalignment within the pulleys will cause a squeaking noise. 

To check and see if it is a pulley misalignment causing the nasty sound, closely monitor the serpentine belt through all the pulleys.

Look for signs of side-to-side movement of the belt. If you notice the belt move this way, you probably need to have a mechanic properly align the pulleys. This should resolve the issue.

Also read: 4 Reasons A Belt Will Squeal (And Easy Ways To Silence It)

Pulley Bearings

All of the pulleys have bearings that help them rotate. If there is an issue with one of the bearings, or if they are worn out, you will notice a squeaking noise. There is a way for you to diagnose worn-out bearings.

Grab a spray bottle filled with water, and squirt some onto the rib side of the belt while the engine is running. You must be very careful and steer clear of the running fan, which can seriously injure you.

If the noise disappears when you spray the belt with water, this indicates that the problem is with the belt, not with any of the pulley bearings. 

If it were a pulley bearing that was making the sound, it would keep coming even after you water the belt. 

Worn-out Belt

Lastly, you will notice a squeaking noise if your belt is work-out. A serpentine belt usually lasts 60,000 to 100,000 miles (96,561 to 160,934 km). We’ll repeat the same method used above to determine if the belt is the culprit.

Simply spray the rib side of the belt with water and see if the noise stops. If it does, it is a clear sign that your belt needs replacement. However, suppose the sound gets louder after applying water. In that case, there is an issue with the tensioner pulley, or the belt is stretched out. 

2. How To Quiet a Grinding Noise?

When you hear a grinding noise from your engine, you first need to turn off the engine and inspect your belt for any signs of debris. Once that’s out of the way, you need to take the belt off and check all the pulleys safely to see if they are making the sound. 

You can do this by jiggling the pulleys and spinning them to look for any signs of unnecessary racket. Once you spot the pulley that is creating the noise, which usually is the compressor, we can move on to the resolution. 

The solution requires you to replace the AC compressor. But before doing that, you also need to ensure there aren’t any contaminants inside the AC system. Since there are filters inside the AC system to catch any debris or contaminants, the system will heat up if there is too much debris. Because of this, your new compressor will wear out faster and blow a hole in your wallet.

Specific tools are used to clear contaminants and debris from your AC system, depending on the model of your vehicle. I recommend taking your car to a good mechanic who can do a complete and thorough job. 

3. How To Quiet a Knocking/Clicking Noise?

This issue is the easiest to fix on your own. A knocking sound indicates that there might be something loose under the hood. Furthermore, you can pinpoint the source of the sound by firing up the engine and turning on the AC. 

If you hear the sound only when you turn the AC on, this indicates the compressor mounting, which might be loose. To fix this, grab a right-sized wrench and tighten the bolts around the compressor. 

4. How To Quiet a Buzzing Noise?

A buzzing sound from your engine means that your AC compressor has excess refrigerant, which can damage the compressor if not fixed as soon as possible. This calls for removing the excess refrigerant from the system, which a mechanic can do in a short time. 

Although, if you feel like you can take on this task on your own, you should watch the video below to get your ducks in a row. 

Alternatively, a buzzing sound could also mean your refrigerant leaks through the pipes. If this is the issue, you will experience low cooling within the car when you turn on the AC. Inspect the pipeline around your engine and look for any hoses that might be covered in oil. Any pipe covered in oil is where the leak exists. 

Also read: Best Ways to Fix Car Rattling Noise When Accelerating

Final Thoughts

Having a car requires ongoing maintenance for hundreds of moving parts. The AC system on your vehicle is one of these parts. If you notice any unusual sounds from the compressor, you should always consider talking to a trusted mechanic.

Although this guide can help you figure out the source of the racket and how to fix it, a mechanic will be able to delve deeper into the issue if you cannot easily resolve it.

Also read: Why Do Brakes Squeak at Slow Speeds?

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