A fridge is a fairly complex machine with multiple parts that need to function properly in order to keep your food chilled and safe for storage. It usually involved a cooling element, a compressor, a fan to circulate the cold air, and other accessory parts like an ice maker and shelves.
One or more of these parts can malfunction and cause issues with how it functions. One of the indicators that your fridge isn’t working correctly is if it makes a knocking noise. The fix could be as easy as checking your ice machine or as difficult as repairing your compressor, with the worst-case scenario being that you have to buy a whole new refrigerator.
But before you start to worry, let’s look at some of the simple fixes.
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Simple Fixes
Double-check these 3 common issues before you begin pulling apart your fridge. The solution may be easier than you think!
Built up Ice
If you usually keep your fridge and freezer on the colder side, it’s possible that ice can build up on various parts around the edges on the inside and even on the fan itself.
As your fridge goes through its cycles of frost/defrost, some of this ice can get knocked down and cause your refrigerator to make intermittent knocking noises.
Check the bottommost portions of the shelves to see if you observe any ice pieces. If you do, you may need to slightly lower the inside temperature to avoid excess build-up.
If the ice is built up around your fan, it might be preventing it from spinning correctly as it catches on the ice during rotation. Instead of an intermittent knocking, you may hear a consistent, rhythmic knocking for several minutes at a time as your fan runs.
You should completely defrost the fridge to remove all the build-up around the fan and then lower the temperature once you start it running again.
Don’t try to break the ice free while the fan is running, this could cause the fan to completely break and then you’ll have to replace it.
Malfunctioning/Blocked Ice Maker
This type of knocking will also be intermittent, and almost clicky, especially in Whirlpool models. You may notice the compressor kick on and then the knocking sound starts.
If this is accompanied by a mechanical whirring, there is most likely something blocking your ice maker arms from pushing out the formed ice.
It could be a piece of ice itself that is preventing the arms from having their full range of motion. It is also possible that one or more of the ice maker arms got bent at some point and they are catching as they dispense the ice.
Thoroughly inspect all of the parts of your ice maker, including the dispensing tray, and try to clear any blockages. If your arms are bent, reach out to the manufacturer for replacement parts.
Loose Pipes
If you have the ice maker on the fridge connected to a water line, you may notice a slight knocking while the tray is filling. This is most likely due to the pipes in the water line moving slightly as the water runs through them.
This can be fixed by moving your fridge several inches forward so it isn’t pressing too hard against the lines, or double-checking that there is a secure fixture plate on the wall where the pipes exit.
If you do not have an ice maker on your Kenmore (or don’t have it connected), this isn’t an issue you will have since water lines are only hooked up to provide water to ice makers.
Complex Fixes
If you’ve checked the previous issues and you are still experiencing knocking sounds, you may have a bigger problem on your hands. It could still be fixed, but it may cost you a bit more money and require you to consult a professional.
Condenser Fan
In order to cool the condenser coils of the fridge, newer models – such as Samsung fridges, have a fan in the back of the fridge unit. It’s hidden under paneling so it’s not easily seen without taking off the back of the fridge.
If you can pinpoint that the knocking is coming from the back of the fridge (and it’s not the water line pipes) it is most likely the condenser fan. Foreign objects can get lodged in the back – even a mouse nest. This can prevent the fan from spinning, as can a large accumulation of dust and debris.
It’s recommended you get an appliance technician to remove the back panel of your fridge & clean the area thoroughly. They will be able to determine if you need a new condenser fan or if a simple dusting will fix the problem.
A new fan might be recommended if the blockage was severe enough to alter how it functions or if one or more of the blades are bent.
Compressor Malfunction
This is the worst-case scenario since a replacement compressor can easily cost more than the price of your fridge. The compressor and the compressor fan are essentially the main cooling elements of your fridge.
It’s very possible that the compressor has simply come loose within its compartment and creates consistent knocking sounds while it is running – particularly right when it turns on and right when it turns off.
This may be easily fixed by tightening the bolts and ensuring that stationary parts of the compressor are securely bolted in.
But if everything is secure and the knocking sound is still happening, it’s most likely a malfunctioning crankshaft within the unit. Sometimes, these specific parts can be replaced or repaired by trained technicians.
Unfortunately, if the entire compressor is going out, the only solution is to replace the compressor (which can be very costly) or replace the whole fridge. Replacing the fridge may indeed be cheaper than replacing the compressor.
An appliance technician will be able to determine the best course of action. Do not attempt to dismantle the compressor yourself.
