Your AC Is Making Strange Noises: What to Do

Posted on August 18th, 2025 by Ferocious Digital

Strange sounds from your air conditioner aren’t just annoying—they’re warning signs. Catching them early can save you from bigger, costlier repairs. If your AC is talking, don’t ignore it. Here’s how to decode everyday noises and what to do next from our Devine Bros pros.

Banging or Clanking

Likely cause: A loose or broken part inside the compressor, a misaligned fan blade, or debris in the outdoor unit.
What to do: Turn off the system to prevent further damage. Check for visible debris around the outdoor unit. Do not reach inside. Call a professional to inspect the fan, motor mounts, and compressor.

Hissing or Bubbling

Likely cause: Refrigerant leak or a high-pressure issue; bubbling often indicates a leak in the refrigerant line.
What to do: Switch the AC off and schedule service right away. Refrigerant leaks reduce efficiency, harm components, and can be hazardous if improperly handled. Only licensed technicians should repair and recharge refrigerant lines.

Clicking

Likely cause: Normal click at startup/shutdown is fine. Constant or rapid clicking can indicate an electrical problem, a failing capacitor, or a faulty relay.
What to do: Don’t cycle the system repeatedly. Check your thermostat batteries first. Call for electrical diagnostics to avoid damage to the control board or blower motor if clicking continues.

Squealing or Screeching

Likely cause: Worn blower belt (in older systems), bad motor bearings, or a failing outdoor fan motor.
What to do: Power down the unit. Continued operation can burn out the motor. A technician can replace belts, lubricate or replace bearings, and test motor amperage.

Rattling or Vibrating

Likely cause: Loose panels, screws, or an unlevel outdoor condenser.
What to do: Tighten accessible panel screws and ensure the condenser sits level on its pad. If rattling persists, schedule a check to rule out internal damage.

HVAC Services in Norwalk, CT

Helping Norwalk homeowners improve their lives at home is something Devine Brothers has been providing to their customers for over 100 years! If you want to learn more about our service or need supplies, contact us today! For more tips & tricks, make sure to like us on Facebook!