What Different AC Noises Actually Mean

Your AC's noise is trying to tell you something specific. Here's how to translate it.

Grinding usually means a motor bearing issue

A grinding sound, especially from the outdoor unit, often points to a motor bearing wearing out — worth having checked before it fails completely.

Squealing often means a belt or motor problem

A high-pitched squeal frequently indicates a belt that needs replacing or a motor that needs lubrication or repair.

Banging can mean a loose or broken part

A loud bang, especially on startup, can indicate a broken connecting rod or a loose component inside the unit — this is not something to keep running through.

Clicking on startup is often normal

A single click as the system starts or stops is frequently just the normal sound of relays engaging — but repeated or rapid clicking is worth investigating.

What to do in the meantime

If a noise is loud, sudden, or new, it's safest to turn the system off and have it inspected rather than let a developing issue turn into a bigger repair.