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Air Conditioner Noises That Might Necessitate A Repair

by Feride Halma

When you turn on the air conditioner, you expect to hear the normal noises, such as a whoosh or a hum. However, when air conditioners break or start to fail, one of the first signs is often an unusual noise. Clicks and whirs that have always been part of the unit are no cause for alarm. However, when you start hearing the following sounds, you may need to call for AC repairs.


One noise you might hear is a banging from inside the AC unit. You only hear this noise when the cool air is on, not just the fan. It's possible that a branch or another object has fallen into the unit, thus causing the banging. The more likely scenario, though, is that some part, such as a piston or crankshaft, is broken and loose inside the unit.


A similar scenario is when you hear more of a metallic clanking rather than banging. Typically, such a sound signifies a loose or out-of-balance part. The culprit is usually the blower motor or the compressor. The sound may also signify fan blades that are out of balance.


Sometimes you turn on the AC and hear a squealing noise. This is often a slipped belt drive or worn motor bearings. The belt drive is part of the blower assembly — it turns the fan. The bearings are part of a direct-drive motor. Either way, they require repairs when they're out of whack.


Perhaps the sound is more high-pitched than a squeal — it might actually be a screaming sound. If you hear that noise, turn your air conditioner off. You may have a refrigerant leak or high internal pressure inside the compressor. Both situations are dangerous to both your safety and the function of the unit.


Your AC unit shouldn't hiss like a snake or make bubbling noises. If it does, you probably have liquid inside the unit. Indeed, a hissing or bubbling sound is another indicator that you have a refrigerant leak. What you're hearing is air bubbles inside the refrigerant line. Your AC unit can't function properly in this state.


Unfortunately, the sound of a buzzing air conditioner unit is a bad sign. It usually indicates that the unit has an electrical problem and is failing. For instance, the motor might be failing or the compressor malfunctioning. You might even have arcing, which is electrical currents arcing outside of their intended paths. The capacitor might also be broken.

Call for AC repairs if you hear any of the above sounds.