Refrigerator Makes Knocking Noises? (How To Diagnose)

Upgraded Home Team
by Upgraded Home Team

Abnormal noises that come from a refrigerator can be off-putting, especially when you don’t know what they mean. It can be disconcerting when your refrigerator makes knocking noises, especially if it happens constantly. So, what does it mean when your refrigerator makes knocking noises?

A refrigerator makes knocking noises when the condenser coils are dirty or if the compressor is damaged. The placement of your refrigerator also affects how noisy it is, and it can make knocking noises if it is too close to a wall or cabinet. A condenser fan can also produce a knocking or banging noise if it is damaged.

Always unplug your refrigerator and pull it away from the wall before you examine a particular component. Let the refrigerator cool down for up to 20 minutes before you attempt to replace a compressor because it can get hot. Follow along as we explore what it means when your refrigerator makes knocking noises.

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Refrigerator Makes Knocking Noises

The most common reason that a refrigerator makes knocking noises is that moves against the walls or cabinets. Refrigerators sometimes move slightly during operation, and this can be loud if it bangs against the wall. This is more common with older models, but it can happen to any refrigerator that is backed against a wall, countertop, or cabinet.

Step 1: Move the Refrigerator

To fix the issue, you will need to adjust the refrigerator’s position. Start by sliding out the fridge from the wall and pulling it out carefully. Check to see how far the electrical cord can stretch, as you still want it to connect to the wall outlet.

Step 2: Measure It

Take a measuring tape and measure around 1”-2” on each side. This will be the perfect length to prevent the banging sound from occurring. Place your refrigerator carefully so that there is enough space on each side or else it will continue to knock and bang.

Step 3: Place Foam Wedges

You may not have enough room to give your refrigerator 2” on each side. In that case, you can stop the knocking noises if you place foam wedges on each side to soften the impact and reduce noise.

If the space between the walls, counter, or other objects is tight, you may not fix the problem. We’ve found that placing foam wedges in between the areas can help reduce noise.

Bad Compressor

The compressor is responsible for keeping your refrigerator cool, and it can be loud when it runs. However, a bad compressor can produce loud knocking sounds within your refrigerator. Unfortunately, you cannot repair a compressor, and you’ll need to replace it.

Step 1: Find the Compressor

Read your refrigerator’s manual to find out where the compressor is located. You can find the compressor in the back of a refrigerator in most modern units. Unplug your refrigerator or shut off power to the circuit from the breaker to prevent electrical harm.

Pull the refrigerator out from the wall with the help of a friend because they weigh up to 250 pounds. Look for the black box object towards the bottom at the back of your fridge.

Step 2: Replace the Compressor

Remove the protective plate from the compressor with a socket wrench and expose the compressor. Carefully remove the 2 wires from the compressor, pull the compressor out, and install the replacement. Make sure to connect the wires to the new compressor at the same terminals as the old compressor.

How to Clean a Compressor

The other method to prevent noise is to clean and repair the compressor. If you don’t know how to do any handy-work, we suggest calling in a professional. They can help you move the refrigerator and clean the compressor’s components. If a replacement is needed, they can also help install a new component. However, you’ll have to weigh the pros and cons of replacing the compressor on a refrigerator.

Step 1: Move Fridge

The first step you’re going to want to take is to move the fridge from the wall. Move the refrigerator all the way out so that you can see the bottom back panel. You’ll also want to unplug the fridge for the time you’re working on it.

Step 2: Open Fridge Up

Open the back panel of the fridge to locate the compartments. The compressor should look like a small black box with wiring attached to it. It features an egg-like shape in most modern-day refrigerators.

Step 3: Clean Compressor

Using a damp cloth, go ahead and wipe down the exterior of the compressor. From there, you can use a can of condensed air or a small brush to clean in between the creases. A q-tip can also help clean the small, compact areas.

Step 4: Test

Once you’ve cleaned out the area, you can then test the fridge. Put it back together and close the panel. After that, wait to see if the refrigerator produces any sound. If it does, you may have another problem on hand.

Clogged Condenser Fan

Another common area that can produce a knocking sound is the condenser fan creating noise. The fan can become clogged with debris, dirt, and even lint. When it is clogged, it reduces airflow and can cause a knocking or whistling sound.

Step 1: Unplug & Move

Luckily, repairing it is an easy fix. To fix the condenser fan, start by disconnecting the power. You’ll need to unplug the unit and cut off the electrical current altogether. After that, you will need to pull the refrigerator out until you can stand in the back.

Step 2: Remove Back Panel

Once you can access the back of the refrigerator, you can then remove the thin panel. The panel is located near the ground and holds all of the refrigerator’s essential components. You’ll need a screwdriver to remove the panel.

Step 3: Clean Condenser

After removing the panel, use a soft brush or dry towel to clean around the fan. If there are any small areas, you can’t get into, you can use a q-tip. Don’t use a wet towel to mess with the electrical current when it is turned back on.

Dirty Condenser Coils

Condenser coils can easily get dirty, and it often explains why your refrigerator makes knocking noises. You should always clean your condenser coils at least once per year because a buildup of dirt, grime, lint, and leftover food residue can coat them. Dirty condenser coils are more likely to wear out quickly, and your refrigerator will operate loudly.

One sign of a dirty condenser is reduced cooling in the refrigerator. If the food inside your refrigerator is perishing quicker or notice it doesn’t feel cold to the touch, then the condenser could be the problem.

Everyday noises from a dirty condenser is a knocking, ticking, or popping sound. The condenser is attempting to function with debris in the way. This is what creates a loud sound.

Step 1: Move Fridge

The coils are located in the back of the refrigerator near the compressor. To access it, you will need to pull out the fridge and get behind it.

Step 2: Remove Back Panel

The condenser coils will be behind a panel. You will need to remove the outer panel using a screwdriver.

Step 3: Locate Coils

Once you have open access to the refrigerator’s inside components, you can locate the coils. They look like a set of black devices and should be near the condenser fan. If you have trouble finding them, then you’ll need to pull out your refrigerator instruction manual to locate them.

Step 4: Clean Coils

After you find the coils, you will then need to wash them. To clean the condenser coils, you will need to use a soft brush or dry towel. Other areas around the coils can get dirty as well. Since you’re already cleaning that area, you can go ahead and clean the others.

Step 5: Clean Surrounding Area & Put Back Together

If it’s dusty or dirty behind the refrigerator, we suggest using a vacuum to clean the dust and debris. A desk keyboard vacuum or compressed air duster also works. After you’re done cleaning, you can put the refrigerator back into place.

Evaporator Fan Motor or Blade

Another area that contributes to fan knocking is the evaporator fan and coils. The fan and coils are located in the freezer compartment. If the knocking only happens when you open the freezer door, it’s an issue with one of the two areas.

How to Fix Fan Motor/Blade

Step 1: Remove Panel

You’ll need to remove the inside of the panel to gain access to the freezer compartment. To do this, you’ll need to take out everything in your freezer. The screws will be located on the back of the inside of the refrigerator.

Step 2: Inspect Fan & Blades

Inspect the fan and the blades to see if they are intact. If there is a crack or damage, you will need to contact the manufacturer for replacement parts. Calling a professional can also help if you’re unsure how to uninstall or reinstall fan blades.

Step 3: Inspect Wiring

Lastly, see that all the wiring is connected correctly. Sometimes the wiring can have debris or ice buildup inside of the components. If this happens, you’ll need to contact a professional to help repair the device.

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Upgraded Home Team
Upgraded Home Team

We are a team of passionate homeowners, home improvement pros, and DIY enthusiasts who enjoy sharing home improvement, housekeeping, decorating, and more with other homeowners! Whether you're looking for a step-by-step guide on fixing an appliance or the cost of installing a fence, we've here to help.

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