Outside AC Unit Making Loud Noise, What May Cause It and What to Do About It?

The latest technology implanted in the modern air conditioning unit is engineered to help the appliance make an as little sound as possible while operating. Therefore, if you hear the outside AC unit making loud noise, it can be a sign that something needs to be repaired or replaced.

The following post will help you to diagnose the problem according to the noise type and what you should do to solve it.

Why Is My Outside AC Unit Making a Loud Noise?

Identifying what kind of noise that your air conditioning unit makes will assist you in discovering the cause and fix quickly. Here are some of the most common unusual sounds produced by AC:

outside ac unit making loud noise


A screeching sound of an AC unit resembles the noise made by metals grinding against each other.

There are two possible causes of this issue. The first possible cause is a broken condenser fan engine because it can produce such a squealing or screeching noise if it operates in a damaged state. The second potential reason is a faulty compressor—a component that’s responsible to circulate the gas or liquid that brings down air temperature across the building.


If you hear a loud noise from the air conditioning that sounds like a banging noise, there are several possible reasons behind this. First, the aging springs that are supposed to offer balance to the compressor.

Broken springs eliminate the balance of the compressor and make them bang when in contact with other close parts. Second, if the unit clashes with the condenser fan, which most likely is caused by loose components of the fan.


A popping noise made by an outdoor air conditioning unit is typically a sign that the compressor is drawing the refrigerant while it is still in its liquid form. The refrigerant is responsible for absorbing the warm air’s heat drawn out from the house and then turning it into a type of gas or vapor.

The warm-temperature gas then should enter the compressor. However, if the air conditioning unit isn’t working properly, the compressor is sucking up on liquid refrigerant instead of warm gas, which may result in a damaged compressor.

Make sure that you turn off the AC system immediately if you hear the popping noise created by the unit.


An unusually loud buzzing noise indicates an electrical issue with the outdoor AC unit. Some of the possible reasons that cause this situation are loose frayed wires, broken condenser fan or compressor, damaged capacitor, or damaged compressor. You will need to contact a professional to determine the exact reason and repair the issue.


If your AC outdoor unit produces a hissing sound, refrigerant leakage is most likely caused. Refrigerant goes through circulation across the building using copper lines that operate in a recirculating system.

This means the refrigerant shouldn’t run out except if it’s experiencing some kind of leak. A hissing noise can be heard when the refrigerant seeps through the cooper tubes due to the pressure difference, like when the air flows out of a balloon.

On the other hand, if your AC unit making loud noise when heat is on, the causes can be due to a worn-out system or improper installation. This problem may require you to repair or replace the unit.

Outside AC Unit Makes Loud Noise When Starting

No air conditioner should make a concerning noise if it operates normally, so if it does, there’s a good chance that the system is damaged. It is recommended to call an expert whether you discover that the indoor or outside AC unit making loud noise.

This way, any problem may be fixed before it turns into a more extensive scale, an issue that may cause you to put out a lot of money, effort, and time.

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AirconMag is an experienced author and Air Conditioner expert. With years of practical experience in the field authored several informative articles on various aspects of AC unit, including installation, maintenance, and repair