man looking confused by air conditioner
July 2, 2021

Weird noises coming from your air conditioner are almost never a good sign. Air conditioners are designed to operate as quietly as possible, and while most ACs will make a low humming noise while they’re running, anything out of the ordinary can be cause for concern. 

Knocking and clunking noises are particularly unsettling and can indicate a serious problem. If you hear an AC clunk noise, or a knocking noise when your air conditioner is on, the issue could be that: 

The Compressor Fan Is Loose 

If the knocking noise is coming from your AC compressor (the outdoor unit), the fan or one of its blades might be loose. This can cause the fan’s blades to bang into other parts of the compressor, creating a loud knocking noise. 

There’s Something Stuck Inside the Compressor 

Because your AC compressor unit is located outside, it’s not impossible for small objects like twigs and acorns to fall inside the unit. If this happens, and the object gets in the way of the fan, the fan will hit it. Depending on the material of the object, this could cause a knocking or banging noise. 

Another Part Has Come Loose 

There are several pieces of your air conditioner that may become loose or detached over the years, such as the piston pin, crankshaft, connecting rod, or even just a screw. Once loose, these pieces will be banged around inside your compressor, which can be noisy. 

There’s a Problem With the Blower

Central air conditioners use a blower, which is essentially a fan, to push air through your ductwork. When there’s a problem with your blower, you may start to hear any number of strange noises coming from your air conditioner, including knocking and banging noises. 

Solve the Problem Fast With Air Conditioner Repair Near You in California 

Knocking and clanking noises can be caused by any number of problems, some of which are more serious than others. Here at Greiner, we offer professional repair services for central air conditioning and ductless mini split air conditioners. We can inspect your unit, find out what’s causing the problem, and recommend the best solution. We also offer affordable, preventative maintenance plans, which will help you avoid AC damage in the future. 

Loose parts can often be screwed back into place, but more serious damage may require either replacing a part or, in some cases, replacing the unit altogether. We’ll always try to save your existing AC unit if we can, and we’ll never try to sell you a replacement unless we know it’s in your best interest. 

Looking for home AC repair near you in Davis, Dixon, or Vacaville, CA? Contact us online to schedule a service call. 

Is your AC making loud noises? 

Schedule AC repair today. 

Schedule Service

SCHEDULE NOW
For service, replacement, solar and home-performance energy upgrade projects