Is your fridge suddenly a lot louder than normal? Refrigerators make many sounds we might expect, such as water dripping, the fan turning on or off, or the motor operating. However, other sounds are a little more unexpected, such as a fridge making knocking noises. While the reason for the knocking sound may be as simple as the refrigerator vibrating against a wall, the sound may also have other sources that you'll need to investigate.
Fridge Banging Noise From Contact
One basic reason that a fridge makes a knocking sound or vibrating sound is the movement of the refrigerator against surrounding surfaces, such as a wall. It's easy for your refrigerator to get pushed up against the wall or surrounding cabinets. The appliance naturally has some vibration to it as it operates, so the sound can be more noticeable when it's touching another surface. To resolve this problem, pull the refrigerator out so that there are a few inches of space between the refrigerator and any other surfaces.
Compressor Starting or Stopping
Another primary source of a knocking sound is the compressor, which may knock when it is starting up or shutting down. This is most common in older model refrigerators, so if you have a brand new fridge making noise, the compressor probably isn't the issue. The compressor is located behind the back panel on the unit and should not be accessed by most homeowners. Contact a professional for service if you suspect the compressor is to blame for the noise, as the compressor may need to be cleaned, repaired or replaced.
Clogged Condenser Fan
While the most likely reason for a refrigerator to make a knocking sound is the compressor, the condenser fan might also cause a fridge banging noise. This may occur if the fan becomes clogged with lint or other debris, which reduces air flow and makes a clicking, knocking or whistling sound. Disconnect the power to the refrigerator and remove the thin panel on the rear of the refrigerator. Use a soft brush to clean the fan, and then replace the cover plate.
Dirty Condenser Coils
The condenser may get covered with dirt or lint. When this happens, the condenser can make a noise when operating and cause reduced cooling in the refrigerator. If you hear new noises and notice the fridge isn't cooling as well as normal, check on the condenser coils to see if they're dirty.
The coils are a set of black devices, usually located on the back of the fridge next to the condenser fan. Pull the fridge away from the wall to look for the coils. They may also be located at the bottom of the fridge. You'll need to remove the cover near the bottom of the fridge to access them if that is the case. Refer to your fridge owner's manual to find the location of the coils on your specific model and learn how to access them.
You can clean the condenser coils with a soft brush when cleaning the condenser fan. Then remove the grill and finish cleaning the condenser from underneath the refrigerator. You can also use a vacuum to clean dust and debris out of the area.
Meredith Jameson writes early childhood parenting and family health articles for various online publications. She holds a Bachelor of Arts in history from San Francisco State University.