Refrigerator Knocking: 5 Easy Ways To Fix The Problem Now

The refrigerator is one of the appliances invented for your convenience, but sometimes this convenience is lost by the noises coming from your refrigerator.

The sounds can be the Compressor clicking when powered on or the fan humming while spinning. These noises some people can get used to these over time, but the knocking sound is different.

The knocking sound is loud and weird, which can alarm you that something is wrong with your refrigerator. If you hear this sound, don’t worry, you have come to the right place.

In this article, I will discuss all the reasons behind your refrigerator knocking and how to fix each reason quickly.

Why Is your Refrigerator Knocking?

When the ice builds up around the evaporator fan, it results in the knocking sound you hear. In addition, the water pipes fixed behind your fridge can be responsible for the noise.

I will discuss all the possible reasons you are hearing this noise from your fridge, and then I will tell you how to fix each one.

1- Evaporator Fan Ice Buildup

The first step when troubleshooting the knocking sound is to check the evaporator fan to see if there is an ice buildup around it. The evaporator fan is responsible for refrigeration inside the refrigerator compartment and cooling the evaporator coils.

The fan draws the heat from the fridge, then releases and distributes the cold air in the fridge compartment to cool the temperature. The evaporator fan doesn’t differ from any regular fan; it consists of a fan motor and blades.

When the ice builds up around the evaporator fan, the blades will start to hit the ice as they spin. The constant friction between the blades and the ice produces the knocking noise you hear.

2- The Water Pipes Fixed Behind the Fridge

If your fridge has an ice maker or water dispenser, the fridge needs a water supply. Therefore, you will find hoses and pipes connected to your refrigerator’s back.

The pipes and hoses can sometimes move back and forth, hitting on the back of your fridge and producing this knocking sound. The reason behind this movement is the unstable water pressure in your household or the water hammer effect.

If the water pressure in your household is unstable or changes drastically, it makes the pipes and hoses move and hit the fridge.

3- Defective Condenser Fan

After checking the back of your refrigerator, and found that the pipes and hoses are not the reason behind the knocking noise. This makes the condenser fan the possible cause.

The fan can start hitting other objects at the back of your fridge. Also, if there is an ice buildup near the condenser fan blades, it will result in a constant knocking sound.

The condenser fan is responsible for cooling the coils; if the condenser fan is defective, the coils will overheat. As a result, this will increase the temperature of your refrigerator.

4- Ice Maker is Blocked

If your fridge has an ice maker, you are familiar with the ice maker job; it forms the ice cubes and pushes them into the ice tray or bins.

In some refrigerator models, the door can have a dispenser supplied by the ice maker. During the ice cube sliding, if an ice cube gets stuck or jammed in the ice maker when the ice maker moves, this will result in a knocking sound.

The ice cube jammed against the parts of the ice maker can prevent the ice maker from functioning, and you will hear continuous odd noises.

5- Plastic Parts of the Fridge

The plastic parts of your fridge can be the reason behind that knocking noise; each refrigerator has a lot of plastic parts and panels inside it. As a result, the air can get trapped behind these parts and panels.

Any refrigerator passes through different cycles throughout the day. The refrigerator has a cooling cycle and then a defrost cycle. So, the air inside the refrigerator and the spaces behind the plastic parts will contract and expand.

The air contracts as the cooling cycle starts and expands when the defrosting cycle starts. The expansion and contraction of air in the spaces result in the “POP” sound you hear, which can be loud enough to confuse it with the knocking sound we are talking about.

The “POP” sound is typical and doesn’t mean there is any problem with your refrigerator. So you don’t have to worry about it.

6- Defective Compressor

After ensuring that all the mentioned parts are not the reason behind the knocking sound you hear, the Compressor is the last to check.

The Compressor is essential for your refrigerator; it’s considered its heart. The refrigerant liquid is compressed in the Compressor and distributed throughout your fridge’s cooling system.

The usual lifespan of a compressor is ten years or more, but if you hear a knocking sound from your Compressor, it means that it has either a defective component or a faulty compressor.

How to Fix a Refrigerator Knocking?

I have walked you through all the possible reasons why your refrigerator has a knocking sound. Most of the reasons are minor problems and don’t mean you have a severe issue with your fridge. Now, I will explain to you how to fix each reason easily.

1- How to Fix Evaporator Fan Ice Buildup?

The easiest way to remove the ice buildup around the evaporator fan is to defrost your refrigerator. Kindly follow the following steps to defrost your fridge if the ice buildup is hard to remove:

  1. Empty your fridge by removing all the food and items. It’s advised to put them in a cooler to stop them from spoiling.
  2. Take out the drawers and shelves from your fridge.
  3. Power off your refrigerator by unplugging it from the outlet.
  4. Open the refrigerator’s door to let the ice buildup around the evaporator fan melt.
  5. Let the fridge open for at least 8 hours if the ice buildup is hard.
  6. Use a fan but don’t use a hairdryer to speed up the melting process if you are in a rush.
  7. Wipe the fridge using towels.
  8. Put back the shelves and drawers.
  9. Put your food and items back.
  10. Power on your refrigerator.

2- How to the Water Pipes Fixed Behind the Fridge?

If your household’s water pressure is unstable, you must hire a plumber to help you fix this problem. You should also ensure that every connection in your plumbing system is tight.

Next, you must ensure that the hoses and pipers installed on your fridge’s back or the wall behind the fridge is secured. Solving the unsecured pipes and hoses will fix the knocking noise if the water pressure problem can’t be solved.

Therefore, try to mount the hoses or the water pipes on a flat surface to prevent them from moving even if the water pressure changes.

3- How to Fix a Defective Condenser Fan?

Before replacing your condenser fan, check it to determine if it’s defective. Kindly follow the following steps to check it:

  1. Unplug your refrigerator.
  2. Move the refrigerator away from the wall to give you access to the condenser fan.
  3. Remove the rear panel to see the condenser fan.
  4. Inspect the fan for any damage.
  5. Let the fan defrost if it’s frozen or has an ice buildup near it.
  6. Try to rotate the fan using your hand to determine if it’s damaged.
  7. Remove anything obstructing the fan from spinning.
  8. Replace the fan if it doesn’t spin at all.

4- How to Fix Ice Maker is Blocked?

The obvious solution to this problem is to remove the ice cube blocking the ice maker. However, before trying to remove the ice cube with your bare hands, you must power off the refrigerator.

The ice maker has different moving parts; therefore, you must unplug the fridge before removing the ice cube. If you are uncomfortable sticking your hands inside the ice maker, you can defrost the ice maker.

5- How to Fix a Defective Compressor?

As I mentioned, the Compressor is an essential part of your refrigerator, but unfortunately, you can not repair or troubleshoot it yourself, as stated by the US Environmental Protection Agency (EPA).

Only qualified and certificated personnel can troubleshoot the seal system of your refrigerator. Therefore, you must hire a qualified technician to help you fix the Compressor or replace it to restore your refrigerant cycle.


The following questions are the most asked ones related to understanding the reason behind the knocking sound from your refrigerator.

1- What is the Quickest Way to Defrost a Fridge?

The quickest way to defrost your refrigerator is to activate the heating element inside your fridge. This will force the defrost cycle to start, and as a result, all the ice buildup will start melting.

To force start the defrost cycle or to activate the heating element. You will need to check the user manual of your fridge because the activation steps differ from model to model and make to make.

2- Can a Freezer Be Defrosted While It’s Powered On?

Yes, there are many ways to defrost a freezer while powered on. The first way is to force the defrost cycle of your refrigerator, which activates the heating element.

The second way is to boil some water using a pot and let the pot cool down inside the freezer. The steam from the pot will melt down the ice buildup inside your freezer.

3- Can You Speed Up the Melting Process Using Hairdryer?

No, it would be best if you didn’t use a hairdryer to speed up the melting process because the hot air from the hairdryer can damage the blades of the evaporator fan.

If you want to use the hairdryer, ensure that you don’t hold it over plastic parts inside your fridge. You should use a fan or hot water to speed up the melting.

4- Can the Compressor Be Fixed?

Yes, the Compressor can be fixed, but it’s not usually because when it starts to make loud noises, it means that the Compressor has reached its last days.

Therefore, it’s not a sure thing, but the technician will repair the Compressor if possible or advise you to replace it.

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