Refrigerator Makes Knocking Noises? (How To Diagnose)


Refrigerator Makes Knocking Noises

Refrigerator noises aren’t usually heard until the dead of night when you go to lay down. Sometimes, a refrigerator can produce a knocking noise. This knocking noise can be startling if your refrigerator never made this sound before.

Knocking noises are made due to both natural functions in the refrigerator and issues with components. The best method to reduce knocking noises is to identify the source. If the noise is due to a problem with the components, cleaning the refrigerator or fixing parts can help prevent the noise.

If you’re worried about the lifespan of your refrigerator, then don’t worry. Most knocking noises can be repaired with a few simple fixes. Below, we’ve listed everything you need to know about a refrigerator that makes knocking noises.

Are Knocking Sounds Every Normal?

Yes, in specific models of refrigerators, the valve and dampeners produce a knocking sound. This is because they work to control airflow in the fridge. When they are working correctly, they can produce knocking noises.

Other instances where a knocking sound will be normal is when the refrigerant is circulating. This happens when refrigerant turns from a gas into a liquid form to help absorb air inside the freezer. After the refrigerant turns into a gas, it then evaporates into the compressor. When the pressurized gas is pushed through the condenser coils, it will turn into a liquid, and the cycle repeats.

Lastly, a loud knocking sound can be heard when the water hammer starts. A water hammer is when the water is pushed to change directions in a water line. What this is called is a hydraulic shock. This happens when the refrigerator is producing ice cubes or dispensing water.

How to Fix Banging Noise

When the refrigerator is up close against surrounding surfaces, it causes friction. The friction can be one reason for you to hear knocking noises. Commonly, we see that the refrigerator is right up against a wall, cabinet, or countertops.

Step 1: Move

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

Take a measuring tape and measure around one to two inches on each side. This will be the perfect length to prevent the banging sound from occurring.

Step 3: Consider

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.

Compressor Starting or Stopping

Another source that could be creating a knocking sound is the compressor. The compressor can make knocking noises when it’s shutting on or off. It will happen at random times, which can be startling.

However, there are two methods to prevent noises with the compressor;

Replacing Broken Compressor

If your compressor is broken or well beyond fixing, you’ll need to replace it. It’s not recommended for you to replace the compressor yourself unless you’re familiar with tools. Here are the steps you’ll need to take to replace it.

Step 1: Find the Right Compressor Part

Each fridge company uses different components, and you’ll need to find the right replacement. To do this, read the instruction manual. If you don’t have it, consider contacting the company you bought the fridge from. They will be able to point you in the right direction.

Step 2: Move Fridge

Once you have the right compressor part, move the fridge from the wall. You will need to locate the compressor, which should be at the bottom of the refrigerator.

Step 3: Replace

Find the fridge compressor, which should be a black box with wires connected to it. Unscrew and remove all attached wires if possible. If you can’t remove the cables yourself, you may either need to contact a professional or replace the whole fridge.

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.

How to Fix Condenser

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

Another common problem with most modern-day refrigerators is that their condenser gets dirty. A buildup of dirt, grime, lint, and leftover food residue can coat the condenser. If you’ve never done refrigerator maintenance, your refrigerator can become worn down.

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.

How to Fix Dirty Condenser Coils

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.

Related Questions

What to do if a brand new refrigerator makes a knocking noise?

A new refrigerator is going to make some knocking noise. It’s best to know which refrigerator brands to avoid.  More recent models of refrigerators are designed to be efficient. Due to this, some of the features produce noise. Temperature control, defrost, and even producing filter water and ice all require functions.

When the refrigerator does these functions, then it can produce a knocking noise. So, if the noise isn’t continually being made, then the noise is normal. However, if the knocking is frequently happening, you may have a problem on your hands.

Is a noisy fridge dangerous?

Yes, a noisy fridge is dangerous if the frequency of the knocking is high. If you feel like the knocking happens continuously, you will need to run a checkup on your refrigerator or call a professional. Diagnose the problem by observing the condenser, fans, and other areas of your fridge.

If the unit is dirty, then you may need to clean the compartments. However, if there are leaks, cracks, or damaged wires, you will need to call a professional. A professional will know how to order replacement parts for each refrigerator model. Hence, you won’t spend time ordering a different part on accident or installing a component wrong.

What to do if the refrigerator noise stops when the door opens?

When you open the door to your fridge, it turns the evaporator fan off. This is because it’s used to regulate cold air. When the refrigerator is open, this function is turned off; otherwise, it would be pushing cold air into your kitchen.

How long is my refrigerator’s warranty?

Each company has a different length when it comes to warranty coverage. Some companies offer a one year warranty while others provide a ten-year warranty. To check what your fridge’s warranty is, head to the manufacturer’s website. The best method to check the warranty is to contact their support and ask about it.

Upgraded Home Team

We are a team of homeowners and home improvement enthusiasts who enjoy sharing decorating, gardening, home improvement, and housekeeping tips with other homeowners! Whether you're looking for advice on furnishing your living room or the next outdoor DIY project, we've got you covered.

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