If there is one thing car owners worldwide hate is noise. Car owners hate noises coming from their cars.
One car component known to sound off once in a while is a car’s AC compressor.
The noise AC compressor can make a car owner or driver and occupants inside a car irritated.
With this in mind, car owners are always looking for causes and possible solutions. With this, we’ve put up this post, AC compressor noise at idle – causes & solutions.
What Are The Types Of AC Compressor Noise?
Before jumping deep into the topic, it is vital to understand the types of AC compressor noise you’ll likely hear at idle.
There are numerous types of AC compressor noise at idle. However, there are four widespread, and they are the ones we’ll highlight below.
These four are whirring types of noise, rattling or rubbing noises, humming and squealing noises, and high-pitched whining noises.
Why is it important to take note of these four?
If the AC compressor noise at idle is rattling, buzzing, humming, and high-pitched whining noise, you should be concerned.
Is An AC Compressor Noise At Idle Normal?
While this might surprise you, an AC compressor noise at idle is normal. Good to note that an AC compressor noise at idle is usually a whirring type of noise.
This whirring noise is because of both the car’s fan and motor working or operating as they should. In some instances, they might and will make this noise.
Do keep in mind that there are instances where an AC compressor whirring noise might be a sign (continue reading for more on this).
While on the subject of AC compressor noise at idle, you must note the type. We’ve pointed out above that it is a whirring type of noise.
If your AC compressor noise at idle is a whirring type of noise, there is no cause for alarm. In other words, you shouldn’t be worried.
If the noises your car AC compressor makes at idle are like buzzing or rattling, you should be very worried. You should seek professional help from your local mechanic.
AC Compressor Noise At Idle – Causes & Solutions
Now that we have familiarised ourselves with a few things about AC compressor noise at idle, we can shift our attention to causes and solutions.
While there are numerous AC compressor noises, some are very common. They are:
- Whirring Noises
- Rattling/Rubbing Noises
- Humming & Squealing Noise
- High-Pitched Whining Noises
We have already pointed out that an AC compressor noise at idle that is a whirring noise is normal.
While this is so, every car owner must pay attention to the car AC compressor’s whirring noise.
If the AC compressor noise at idle sounds like a helicopter, you might have a mechanical problem with your car.
With an AC compressor noise at idle sounds like a helicopter, you have a faulty fan or the indoor blower, or the outdoor unit is not functioning correctly.
It can be attributed to a faulty fan or a simple bad bearing in the indoor blower. If you are lucky, the problem might not be any of these two.
Yes, you might be getting the helicopter-like noise because of debris or paper stuck in either the outdoor fan unit or the blower.
If you are lucky to have this problem because of debris or paper being stuck in either the outdoor fan unit or the blower, the fix is easy.
Remove the stuck paper or debris. In most cases, this usually does the trick.
If you are dealing with a faulty fan, the indoor blower, or the outdoor unit is not functioning correctly, you’ll need to replace both parts.
This task requires expertise; thus, seeking professional help is highly advised.
Rattling or rubbing noise is another common AC compressor noise at idle. When this situation occurs, something is vibrating against your car’s AC compressor.
There are several causes for this. For instance, it can be because of a hose, fan, or belt.
In some instances, this AC compressor noise at idle results from an AC compressor deteriorating.
A deteriorating AC compressor will have loose parts that might rub off, causing rattling or rubbing noises.
Although not as expected, a small amount of oil on the compressor’s shaft can cause a rattling or rubbing noises.
The fan can also be a cause when it comes to AC compressor rattling or buzzing noises. Fans tend to rattle when they lose, making them a culprit.
One of the advantages (if you can say so) of this particular AC compressor noise at idle is the fix. It is easy to fix.
Make sure that there are no objects that are hitting the compressor. Once you make sure of this, check the belt, hose, and fan.
You want to make sure that they are all connected properly. Equally important, make sure that the fan is functioning correctly.
You should as well (depending on the issue) add oil to the compressor shaft and check for loose screws or bolts in your unit.
Remove any of them if you happen to spot them.
Humming & Squealing Noise
Humming and quelling noises are also everyday AC compressor noises at idle.
With humming noises, the cause is usually a faulty air conditioner or, better yet, something is off inside the air conditioner.
Refrigerant piping and loose parts are also probable causes, given that they cause vibration and ultimately a humming noise.
On the other hand, Squealing noise results from fan noise and blowers.
The noise these two make (rattles, squeaks, and squeals) are transmitted through the duct system and come off as squealing noises.
With humming noises, the issue is usually not that serious. However, keep in mind that if you leave it unchecked, it can lead to other car issues.
An easy fix for this issue is ensuring that loose parts are correctly connected and that the refrigerant piping does not cause vibration.
With squealing noise, the same is also true. The sound is not as severe.
However, you want to make sure that you take care of it. With squealing, you want to ensure that the blower wheel and housing haven’t malfunctioned.
In addition, check to see whether the indoor blower motors and outdoor fan motors are working fine. If they are faulty, a change is the best fix.
High-Pitched Whining Noises
High-pitched whining noises are a result of bearings being bad.
If you are dealing with bad bearings in any of the compartments, then the chances are high that you will hear high-pitched whining noises.
If you are not dealing with lousy bearing, you have a situation where the serpentine belt is wearing down.
The noise is a sign that sooner rather than later, the belt will break.
Like rattling and rubbing noises, a possible fix for high-pitched whining noises is simple. You want to make sure that you check your car’s belt.
Ideally, you want the problem checked by a professional from your local garage. Why?
Given the importance of the belt, it is vital that a professional handle it. Remember, a broken belt can be bad for your car’s engine.
AC compressor noise at idle is nothing new. As already noted down, some noises shouldn’t worry you as a car owner.
Regardless, you always want to see that you note every noise your car makes. Upon noting it down, you can share it with your local or personal mechanic.
You’ll be putting yourself in a position to avoid challenges that come with AC compressor noises when the car is idle.
Patrick started his love affair with cars in his childhood. Over the years, he claims a sturdy hold on his driving skills, along with a thorough understanding of cars. We can expect some interesting, holistic, and pleasurable blogs with his flair for writing and his love for cars.
Being a car enthusiast, Patrick has experience comprising of two decades in which he has ridden some of the meanest and strongest machines in the automotive industry. His previous avatars include an automotive professional, photographer, and journalist, and you will certainly experience the roundness of experience in his piece on this site.
In his second decade of reviewing cars and analyzing tools, Patrick is all set to give you convincing, reliable, and the latest information regarding what’s happening in the automotive industry. Currently, he owns a BMW Z3 but cannot get his eyes off Aston Martin DB5. He is a car enthusiast; he loves cooking and listening to music, especially jazz. Here are some of the pieces written by our ace author.