What Does that Noise from My Outdoor AC Unit Mean?

Woman covering ears because of a loud air conditioner

There are lots of summer sounds that are music to our ears like crickets chirping and birds singing. But if you hear sounds coming from your outdoor air conditioning unit, you’d better pay close attention.

Take a look at these noises that might indicate your outdoor AC unit is having an issue:


It might sound like a slamming or a banging noise, but what likely is happening is a loose fan that is making noise as it spins. Banging could also mean there are loose parts inside the compressor.

Shut off the unit and call a professional to service the fan before it damages other internal components.


If your unit is making a buzzing sound when it’s on, it might indicate an electrical problem. Turn the system off and have an AC system professional examine the unit.


If you hear high-pitched, squealing sounds from the compressor, it may signify high internal pressure inside the unit. In that case, you should shut off the unit and call a professional.

A similar sound can also be caused by dry fan motor bearings or a loose fan belt. An AC tune-up can prevent this type of AC issue.


Either you have a snake trapped in your AC compressor, or there’s a refrigerant leak somewhere within the system. The refrigerant can make a hissing sound as it escapes.

Depending on the age of your unit, a leak in an older unit could release Freon into the air or Puron refrigerant in newer units. In either case, refrigerant leaks should be handled by a professional.


Metal on metal rubbing together can make a screeching sound and mean the bearings in your fan motor are going bad.

Continuing to run the AC unit after hearing this sound can further damage the compressor, so you should turn it off and call a professional.

Larry & Sons Can Diagnose & Repair Strange Air Conditioner Noises

If strange sounds are coming from your AC system, Larry & Sons can help with professional repairs. Our family-owned plumbing, heating, cooling, drain, and electrical company has been a part of the business community of the tri-state area for nearly 60 years.

Tell us what sound your AC unit is making, and we’ve got the experience to know exactly the issue and the skills to fix it right the first time.

Call (301) 733-5428 or contact us online today for all your air conditioning system repairs and replacement needs.