Why does my fridge make a knocking sound

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

Fridges make a lot of noise. Some are normal, but others might lead you to believe there is a problem with it. One such noise is the refrigerator making knocking noise. It’s not always a clear indicator of a problem, but it can still cause homeowners to panic.

Your refrigerator is suddenly making more noise than normal. Is this loud knocking sound coming from the coils or the condenser? It’s important to note that many appliances make lots of noises. The refrigerator may be dripping water, turning the fan on and off, or running the motor. Other sounds are less expected, like a knocking noise.

Why Is My Refrigerator Making Knocking Noise – Troubleshoot And Diagnosid

The reason for the knocking sound could be as simple as your refrigerator vibrating against the wall, but it might also have other causes that will need to be investigated.

Refrigerator is Hitting the Wall

One common reason why refrigerators make a knocking sound or vibrating sound is because they are touching something else. It can be easy for your refrigerator to bump into the wall or the cabinets. The Fridge naturally has some vibration so the sound would seem louder when it’s touching another surface.

To fix this issue, move the refrigerator out of the way so that there is a few inches of space between it and any other surfaces.

Check Condenser Fan Motor/Blade

Next time your refrigerator knocks, try to pinpoint the noise and figure out what is causing it. For instance, do you hear a noise coming from behind or at the bottom of the refrigerator? If so, there is probably a problem with the condenser fan motor or blade. To access this part, you will need to take aside the panel that is usually easy to remove.

If the blades on the fan are dirty, you need to clean them. If they are clean then, you probably need to check the motor. A motor can cause a knocking noise if it is faulty. A faulty motor can be easily replaced and will not require a whole new refrigerator.

Dirty Condenser Coils

If you notice your refrigerator isn’t keeping things cold enough, take a look at the coils to see if they’re dirty. The condenser may get covered with dirt or lint. If this happens, the condenser will make noise when operating and reduce cooling. If you hear new noises, yet notice the fridge isn’t cooling, take off the front panel and look for dirt on the coils.

It’s not always easy to find the coils. They could be behind the refrigerator on the back, on the bottom of the fridge, or on the side of the fridge. Pull your fridge away from the wall to look for them. They will be black in color.  If they’re at the bottom of your fridge, you’ll need to remove a cover to access them.

The coils in your refrigerator are located inside the appliance. There’s no need to call for maintenance or purchase a new refrigerator. You can clean them yourself. To find out how, refer to the owner’s manual for your specific model.

Dust, grime, and lint can accumulate on your condenser fan during operation. The blades of the spinning fan can be bent if a foreign object gets caught in them. All of this can cause a noise that sounds like a knocking from your refrigerator.

Cleaning the condenser coils is a multi-step process. Start by removing the grill and cleaning the underside of the refrigerator. Then, use a vacuum to clean dust and debris from behind the refrigerator. Clean the condenser coils with a soft brush.

Malfunctioning Evaporator fan

If you hear a knocking noise coming from the refrigerator and the inside is warm, it’s probably because of the evaporator fan. This component distributes the cold air throughout the appliance to keep it cool. If it’s not working, your fridge will have trouble being cold enough.

The noise may be coming from the evaporator fan motor. It may not be working properly, there may be an object blocking the fan, or the fan blade might be bent and hitting something when it spins, causing a knocking sound.

Here are steps to take:

1. Remove all food from the freezer so you have room to work.
2. Unplug the fridge and remove all food from inside.
3. Carefully use a hairdryer to defrost ice that is blocking the evaporator fan.
4. If that doesn’t work, take off the panel on the fridge and find the evaporator fan.

If the evaporator fan is not spinning quite right, remove it. Brush off the dirt with a brush, and then try to spin it a few times. If that doesn’t work, something may be stuck around the fan that is preventing it from spinning properly.

If the evaporator fan is bent, it won’t work properly. If it’s out of shape, try to gently bend it back into shape. However, if it’s not balanced, you need to buy a new one right away.

The first thing to do when you sense that the evaporator fan is not working is to call a technician. They will find out if it needs to be replaced or if other parts need to be fixed.

Check Compressor

The compressor is a common cause of knocking in refrigerators; however, if you have a new refrigerator making the noise, the compressor is probably not the cause. The most common culprits are older models, so if you have an older fridge, it may just be its age.

Sometimes, noise coming from your refrigerator can be caused by the compressor. It’s important to know that most homeowners cannot access the compressor without professional services. If you think the noise is coming from the compressor, contact a professional. They will need to clean, repair, or replace the compressor as necessary.

The cost of a replacement compressor for a refrigerator can be very expensive. In many cases, it is far more sensible to just buy a new refrigerator.