Is your fridge making pounding or banging sounds? Before you call a professional, it will help to do some investigating first.

A refrigerator makes a knocking noise when it’s in close contact with a surface, or is an older model with a loud compressor. A clogged condenser fan, evaporator fan, and dirty coils can also cause unpleasant thumping noises. Solutions include repositioning the fridge and cleaning its compressor.

Here, I’ll explore why these things happen – and what you can do about them.

1. Close Contact With Surface

Your fridge will have some vibrating or rattling motions as it operates. They happen when:

  • The refrigerant flows
  • The waterline of the unit operates
  • There are items on top of the fridge

So if your fridge is placed near a surface, say a wall, then you’ll likely hear a knocking sound.

How to Fix

Troubleshooting this issue is simple. It would be best if you moved your fridge a few inches away from the wall or the counters. That way, when it vibrates, it won’t make a thumping noise.

You may need to remove the items on top of it as well. While they make sounds that aren’t indicative of damage, they can be concerning at times.

For best results, give your fridge a space of at least 31 in2. Not only will this prevent knocking noises, but it will provide your refrigerator with much-needed ventilation space as well.

Without ventilation, your compressor will end up running continuously. That’s because there is warm air buildup in the area – resulting from lack of ventilation, of course.

Needless to say, a continuously running compressor will severely affect the lifespan of your fridge. Apart from creating knocking noises, your fridge may end up breaking down earlier than expected.

See also: How Much Weight Can You Put on Top of a Refrigerator?

2. Old Fridge Compressor Either Starting or Stopping

Your fridge’s compressor is the pump that controls refrigerant circulation. It also heats the refrigerant by exerting pressure.

The compressor removes the vapor from the evaporator. This helps keep the substance at a lower temperature and pressure before it’s funneled to the condenser.

Because of these functions, thumping sounds often occur in older models – less so in newer ones. If you continue to hear sounds with your latest model, you may have to try the interventions below.

How to Fix

In most instances, you only need to clean your compressor to stop it from knocking. To do this, you need to:

  1. Unplug your fridge. You don’t want to get electrocuted.
  2. Move your fridge to an open area. It’s hard to clean it well if it’s near the wall. As mentioned, this may be contributing to the knocking noise as well.
  3. Remove the compressor shields. Do note that not all models have this!
  4. Clean the coils to remove the dirt. You can use a duster or vacuum cleaner if the buildup is not that severe. For tougher dirt, use soap and a damp cloth. Only scrub the compressor if necessary. Make sure that you don’t get the other parts wet!
  5. Air-dry the coils. Reinstall the shields as needed.

Ideally, you should clean the compressor for about 30 minutes once or twice a year. If not, it might end up needing repair – or worse, replacement. As for these concerns, it’s best to have a professional fix them for you.

3. Other Compressor Issues

Apart from a dirty compressor, other related issues may cause your fridge to knock.

For one, the cooling substance inside the compressor is quite sensitive. That said, it could end up making noises when moved around. Another possible reason for the noise is that the compressor components have come loose.

How to Fix

You will need to do some detective work to determine the actual cause behind the banging sound:

  1. Listen to where the sound is coming from. Open the fridge door to check if the sound comes from the inside or the outside.
  2. If it’s from inside, remove the evaporator fan. It may be broken or stuck. Either way, the technician will have to replace it.
  3. If it’s from the outside, check the bottom of the fridge. Make sure that it’s leveled when you do so.
  4. Move the fridge back into place. The compressor will turn back on once you do this. If it’s a leveling problem, you shouldn’t hear a thumping sound anymore.
  5. Locate the compressor if the knocking noise doesn’t stop. Look for the cooling fan to see if there are loose parts or some stuck debris.
  6. Do the necessary interventions. Secure the fan if it’s loose and replace it if it’s damaged. Tighten the compressor bolts as needed.

4. Condenser Fan Clogged With Debris

While the compressor is often to blame, the condenser fan can also make some scary sounds. This often happens when the fan is jammed with lint, debris, and other material. They limit the airflow, which results in the fan making a knocking, clicking, or whistling noise.

How to Fix

To fix these noises, you will need to clean the clogged fan. As with the compressor, you need to unplug your fridge first. Next, you need to remove the back panel if your fridge has one.

Clean the fan with a soft brush until you remove all of the dirt. Spin it a few times to loosen anything that may be stuck inside. Lastly, return the panel into position and turn your fridge on again. By this time, it shouldn’t be making weird knocking noises anymore.

5. Condenser Coil Covered in Dirt and Debris

The condenser coils are the black items you see at the back or bottom of the fridge. They’re usually placed near the compressor.

In due time, these devices can get covered with dirt. Such things reduce its cooling function, which then leads to knocking noises.

How to Fix

As with the other fridge parts stated above, cleaning the condenser coil should help stop the thumping noise.

First, you need to locate where the condenser coils are. Refer to your user manual if you’re unsure of their placement.

If they’re located at the bottom, you may need to remove the panel that covers them. Clean the dirty coils with a soft brush. You may also use your vacuum cleaner for a more comprehensive clean.

6. Damaged Evaporator Fan

Your fridge has several fans, one of which is for the evaporator. The evaporator fan’s function is to circulate the cold air in your fridge. So if it isn’t getting as cold as it should, then this part may be jammed or bent.

Expectedly, a damaged fan can make further knocking sounds if it’s hitting another component of your fridge.

How to Fix

It would be best if you started by defrosting your fridge. This will melt the ice that affects the fan’s movement.

If this doesn’t stop the noise, then you should clean the fan manually. Remove the fridge’s panel to access the fan and clean it off with a soft brush. Try to spin the fan manually a couple of times as well. This should help remove some of the stuck debris.

If your evaporator fan is bent, don’t try to reshape it. Your fridge will continue to make banging noises because this will make the fan unbalanced. For this problem, you will need to call a technician to make a replacement.

Final Thoughts

Typically, a fridge shouldn’t make knocking noises. But when it does, it’s often due to placement. Other causes include compressor issues, clogged condenser and evaporator fans, and a dirty condenser coil. While you can troubleshoot these problems yourself, it’s best to seek professional help for replacements and repairs.

Related: How to Reduce Refrigerator Noise

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