As air passes through ductwork in your AC system, it’s not uncommon to hear a barely noticeable humming sound when the air conditioner is running. If the soft hum is replaced by a loud rattle, however, you should call an AC repair technician to investigate. Here are some common causes of the rattling sound that the technician might identify.

Why Is My AC Making a Rattling Noise?

1. Debris in Outdoor Unit

Your central AC system includes an outdoor cabinet that contains important mechanical components, including the condenser coil, fan, and compressor. The casing on this outdoor structure is made of many slats and openings that leaves, twigs, rocks, and dirt can wedge through. If you’ve been hearing a loud rattling sound, it could be this debris moving around inside the outdoor unit. To fix the problem, an AC repair technician can open the cabinet and remove any lingering twigs and leaves. It’s important to clear out the system promptly, otherwise, debris can start to damage the important mechanical components.

2. Motor Malfunctions

AC repair

Your air conditioning system has motors that are responsible for moving refrigerant and air through the system. If one of these components is malfunctioning or broken, it might create a rattling sound. Specifically, the sound could come from broken or bent motor clanking inside the unit. The sound could also stem from a stuck fan motor. A technician will examine the system and repair any malfunctioning components to quiet the noise.

3. Loose Screws & Panels

The outdoor unit has cover panels secured by screws. If the screws are loose, the panels could wobble when the fan motor is running and hit against the side of the cabinet, which may produce a rattling noise. You can use a screwdriver or socket to tighten the loose components and eliminate the noise.


To find out why your AC is making a rattling noise, contact the AC repair technicians at Ecology Air Innovations in Elverta, CA. Since 2015, the air conditioning company has been installing, repairing, and maintaining clients’ AC systems throughout the Greater Sacramento area. Committed to providing excellent customer service, the professionals offer a lifetime workmanship guarantee for as long as you own your home. Take advantage of special offers online and call (916) 640-9464 for an AC repair appointment