Here’s Why Your Refrigerator/Fridge Is Making a Knocking Noise

If your refrigerator is making a knocking noise, it’s not always a sign of trouble. Sometimes, refrigerators are just noisy. However, it’s important to learn the difference between an innocent knocking noise and a problematic one. That’s what today’s article is all about!

More often than not, a fridge making a knocking sound can be easily fixed. All it takes is a component replacement, component repair, and/or proper maintenance. Meaning you should keep your refrigerator clean, but more on that later!

In this guide, we will explain the most common causes for refrigerator knocking noise. This way, you will learn basic diagnosis skills so you don’t waste money. We will also provide easy solutions so you can handle the issue on your own if you feel up to it. If not, hiring professional repair services is always an option. 

In case your refrigerator is making a loud popping noise, we’ve got that covered too.

Refrigerator/fridge noise

Why Is My Refrigerator/Fridge Making a Knocking Noise and How to Fix It

Sometimes, a knocking sound is just a knocking sound. When dampeners and the valve are working properly, they can make a knocking noise. That’s completely normal in certain refrigerator models. So, it’s nothing to worry about. 

If your refrigerator is making a knocking sound, it can also be due to refrigerant circulation. Additionally, the starting of the water hammer can cause a knocking noise. A water hammer is when water is pushed to change directions, which happens when the fridge is making ice or dispensing water. 

However, sometimes, a knocking noise coming from your fridge can mean something’s wrong. Normally, the issue will be very easy to deal with. Let’s take a look at the most common reasons for a refrigerator knocking noise. 

  1. The Refrigerator Is Banging Against a Surrounding Surface
  2. One of the most common reasons a fridge is making a knocking noise is that it’s making contact with something. It’s not difficult for the fridge to get pushed up against surrounding surfaces. Such as walls or cabinets. When that happens, it will vibrate against that surface, creating a knocking noise. 

    Vibration is normal and refrigerators do it when they’re operating. Usually, that vibration is not noticeable at all. Except when the fridge is making contact with something else. 

    To eliminate the noise, all you have to do is move the fridge away from the surface it’s in contact with. You just have to follow two steps:

    • Pull out the fridge carefully.
    • Grab a measuring tape and make sure there are two inches of space on each side, between the fridge and the surrounding surface.

    If the space between the fridge and the surrounding surfaces is too tight to allow two inches, use foam wedges. That will reduce the refrigerator noise if moving it is not an option. 

  3. The Evaporator Fan Is Damaged
  4. If your fridge is making a knocking noise and it’s coming from the inside while the temperature is warmer, it may mean the evaporator fan is damaged. The job of the evaporator fan is to distribute the cold air. So, when it’s not working properly, the fridge won’t have a consistent temperature. 

    Whether it’s because the fan motor is malfunctioning, there’s an obstruction on the fan or the blade is bent out of shape, you need to get the evaporator fan fixed ASAP. To do that, you want to defrost the fridge first. This will melt the ice around the evaporator fan. 

    That could be enough to eliminate the refrigerator knocking noise. If it isn’t, then you’ll have to remove the panel to access the evaporator fan. Once you do that, you want to remove it and clean it well without submerging it in water.

    Then, inspect it to make sure none of the blades are bent. If you do find a bent blade, you’ll have to replace the fan. This guide lays out the process very well. Trying to bend it back into shape won’t do much good because it will still be unbalanced. So, the fridge will continue making a knocking noise. 

    If the fan motor is the issue, then you’ll have to call a professional to get it replaced. This video guide shows you what the process is like, so you can get an idea. We don’t recommend you do this on your own if you don’t have the experience. However, replacing the evaporator fan is something you can DIY if you’d like. 

  5. The Condenser Fan Is Damaged
  6. If you find that the refrigerator noise is coming from the back of the fridge, it could be caused by a bad condenser fan. The condenser fan features condenser coils that transfer heat to the outside of the fridge. The coils get hot, so they need to be cooled down. 

    That’s why they are often exposed, so they can be cooled by air. As such, the condenser fan is located at the back of the fridge. When it’s operating, it’s common for the condenser fan to accumulate dust, grime, and lint. 

    The more dirt build-up, the harder it will have to work to spin. This can lead to a knocking noise. To solve that, all you have to do is clean the condenser fan well and do it regularly. Here’s a video guide that will help! The condenser fan will also make a knocking noise if one of the blades is bent or if it’s malfunctioning. 

    You can diagnose a condenser fan by following these easy steps:

    • Unplug the fridge and move it so you can have easy access to the back. 
    • Once you can access the back of the fridge, remove the thin panel. You’ll need a screwdriver to do this. 
    • When the back panel is removed, take a soft brush or a dry towel and clean around the fan. Do not use wet towels.
    • Clean smaller areas as well with the help of a Q-tip. 
    • Take a look at the condenser fan and check the blades for any bents. If you find a bent, you will need to replace it. 
    • You’ll also want to make sure nothing’s broken and check for loose parts. 

    Most of the time, a thorough clean will be enough. However, if the condenser fan has bent blades or it’s damaged in any way, you’ll need to get it replaced. The same goes if the motor is damaged, which is something a professional should replace for you. This video guide explains the process very well. 

  7. The Compressor Is Malfunctioning
  8. If you’ve checked the evaporator and condenser fans and there’s nothing wrong, the issue could be the compressor. Now, that would be really bad news because the compressor is expensive to repair and/or replace. However, it’s the heart of your fridge. So, if there’s something wrong with it, you need to find a solution right away. 

    It’s very common for the crankshaft inside the compressor to malfunction. However, the compressor could also have a loose part or come lose itself. Whatever the case may be, you need to get a professional technician to diagnose it.

    But before you do that, you should give the compressor a good clean. This can make a big difference and it’s something you can do on your own if you’re careful. The first thing you need to do is move the fridge so you can have access to the bottom back panel. 

    You also need to unplug the fridge and keep it that way the entire time you’re cleaning the compressor. Then, you want to remove the back panel to access the compartments. As mentioned before, the compressor is a black box with wiring. 

    Once you locate it, grab a damp cloth and wide down the exterior. Then, use a small brush or a can of condensed air to clean all the creases. You could also use a Q-tip to get all the small, tight areas. Take your time with this and make sure to get all the dirt and dust off. 

    When you’re done cleaning the compressor, you can put the back panel back on. Plug in the fridge and give it a moment to start working. If the fridge is still making a knocking noise, it means the compressor is damaged. Once you call a technician, they will tell you if it can be repaired or if it needs to be replaced. 

    If they recommend replacement, you need to consider your options. Replacing a compressor is expensive and, in some cases, it’s cheaper to get a new fridge. That’s something you have to look into so you can make an informed decision. If you want to replace the compressor, here’s what you need to do:

    • Find the right compressor replacement. Each manufacturer uses a different component, so finding the right replacement is important. Read the instruction manual or contact the company you bought the fridge from to consult with them. 
    • Once you have the right replacement, move the fridge so you can work on it. The compressor is usually found at the bottom. 
    • The compressor looks like a black box with connected wires. You want to remove all those wires if possible. If you can’t, you’ll have to hire a professional to do this for you. 

    Generally, we recommend you leave the compressor replacement to a professional. This is not something you should DIY because it requires expertise. This video guide can give you an idea of what the process looks like, so you can see it’s quite complex. 

  9. The Condenser Coils Are Dirty
  10. Last but not least, if your refrigerator is making a knocking noise, it could be because the condenser coils are dirty. The condenser will collect dirt, dust, and lint over time. When it gets saturated, it will start making a knocking noise when it’s working. 

    If your fridge is not as cold as usual and you hear noises that weren’t there before, the condenser coils may be dirty. These components are a set of black devices that are usually found at the back of the fridge. They’re right next to the condenser fan. 

    When you’re ready to check them out, here are the steps you need to follow: 

    • Move the fridge so you can get behind it comfortably for the inspection. 
    • The condenser coils are covered by the outer panel. You’ll have to remove it and you’ll need a screwdriver for that. 
    • Once you do, you’ll be able to see all the components inside of the fridge. At this point, you want to locate the condenser coils. 
    • They are near the condenser fan, so locate it and go from there. If you’re having trouble finding them, make sure to check the instruction manual. 
    • After you locate the condenser coils, it’s time to wash them. You can clean them with a dry towel or a soft brush. 
    • You want to be thorough and also clean the area around the coils because it can also get dirty. 
    • Remove the grill and clean the condenser from under the fridge. 
    • Use a small vacuum or a can of compressed air. Remove all the dirt behind the refrigerator and around the condenser. 
    • When you’re done, put the outer panel back on and plug the refrigerator. 

When Should I Call a Professional Repair Service?

Whenever a repair requires expertise, the best thing you can do is call a professional repair service. Cleaning components and making easy replacements is something you can DIY. However, some components are complicated to work with. 

So, unless you have the experience, we recommend you turn to a professional. For example, if you’re having an issue with your compressor or a motor, that’s something an expert should handle. 

Most of the time, a fridge making a knocking sound is something you can solve on your own. Sometimes, all it takes is a thorough clean or moving the fridge a couple of inches. Additionally, some parts are very easy to replace, such as fans. However, don’t do any repairs you’re not comfortable with. 

Your refrigerator is a very important appliance, so make sure to treat it with the respect it deserves. Keep up with maintenance, take good care of it, and pay attention to any new noises. Though they sometimes don’t mean anything, proper diagnosis will save you time and money!

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