AC Making Noise
Different sounds usually point to different problems — here's a plain-English breakdown.
Often points to a motor bearing wearing out — usually worth addressing before it fails completely and causes a bigger repair.
Commonly a belt or motor bearing issue, similar to a squealing sound from a car engine.
Can indicate an electrical relay issue or a failing capacitor — worth having checked rather than ignored.
Often a loose or broken part inside the unit — continuing to run the system can cause further internal damage.
Can indicate a refrigerant leak, which needs professional handling — refrigerant work requires certification.
Frequently an electrical issue — loose wiring or a failing component drawing irregular current.
Frequently asked questions
Depends on the sound. A single click at startup/shutdown is normal. Continuous grinding, banging, or hissing is worth turning the system off and having it inspected before running it further.
Yes — normal operation includes some fan and compressor sound. What matters is a change from your system's normal sound, or new sounds that weren't there before.
See our full AC Repair service or browse other common symptoms.
Decoding the sound — what's urgent and what's wear
Noises map to mechanisms: grinding or metal-on-metal means stop running it now — that's bearings or a blower contacting housing, and runtime converts a repair into a replacement. Screeching at startup is usually belt or motor bearings announcing retirement; buzzing often points electrical (contactor, capacitor, or line voltage) and deserves prompt attention; clicking that never ends is a relay or control trying and failing; rattling is frequently just panels or debris, the one category safe to investigate yourself before calling. Gurgling points at refrigerant or condensate. The honest rule: new noises are information, and the cheap moment to act is while the sound is a symptom rather than a failure. Describe it when you call — the sound narrows our diagnosis before we arrive.