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Carolina Climate Control Blog

Rattle, Clang, Hiss: Warning Sounds From Your AC

As summer gets underway, it’s a good idea to know some of the ways that ACs can give us warnings they aren’t in the best condition. The easiest way to tell when an AC is malfunctioning is when it stops sending out cool air. But we want to help you get ahead of a “no cool” air conditioner if possible with some tips on warning signs you can watch for. Or, in the case of this post, listen for.

Strange sounds are one of the easiest ways to determine that you’ve got a cooling system that needs professional air conditioning repair in Greenville, SC. Anything that isn’t the standard sounds you hear from your AC—the whirring of fan blades, the hum of the compressor, the occasional drip of water, a few clicks as it shuts off—are reasons for concern. Below we’ll look over the most common warning sounds.


This often means that a part of the air conditioner has come loose and is shaking around in it. It might warn that a piece is starting to come loose. You don’t want any loose pieces inside the cabinet of the AC because it will eventually cause damage and that piece was probably doing an important job. Rattling can also warn that the panel to the AC cabinet is loose, and you may only need to close it securely.


The eerie sound of wind whistling through the trees… except it’s coming from your air conditioner. What’s wrong? This might be an easy one for you to correct yourself: check if the air filter is heavily clogged. A dirty filter can create a whistling sound as the blower tries to pull air through it. Put in a clean filter, since a dirty one will create many different troubles for the air conditioner.

Hissing or Bubbling

These sounds have the same source: refrigerant leaks. As refrigerant moves around an air conditioner, it changes between hot gas and cold liquid form. Gaseous refrigerant escaping from a leak will make a hissing, while liquid refrigerant will make a bubbling sound. Any loss of refrigerant puts an AC in jeopardy, so call for technicians to locate the leaks, seal them, and then restore the lost refrigerant.

Loud or Irregular Clicking

As an air conditioner cycles down, it often makes clicking sounds. This is the normal noise of motors cooling off and isn’t anything to worry about. Clicking at other times, or clicking that is loud, can warn of a range of problems, such as failing capacitors and electrical problems in the control board. It can also indicate a hard starting compressor. 


The striking sound of metal against metal is usually a problem with the blower: the assembly may be loose or a fan blade is bent.

Shrieking and Grinding

These sounds indicate problems with motors. A motor’s bearings are wearing down (shrieking) or the motor is burning out (grinding). Shut off the AC and call for assistance right away; if the bearings are wearing down, technicians can replace them and save you from a full motor replacement.

Reach out to Carolina Climate Control 24/7 for air conditioning repair in Greenville, SC. The Moose Is Loose in Your Neighborhood!

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