Why is the refrigerator knocking: finding the causes and methods of eliminating the knocking

Evgenia Kravchenko
Checked by a specialist: Evgenia Kravchenko
Author: Yana Mokeeva
Last update: June 2019

Even the most modern and expensive models of refrigerators can hardly be called absolutely silent. But if clicks, a knock when turning on / off, or other uncharacteristic sounds join the measured buzz of the unit, this device gives a signal that it is time to arrange an inspection with a possible replacement of worn parts.

You will learn all about why the refrigerator knocks and how to get rid of noise, from the article we have proposed. We described in detail the causes of extraneous sounds and methods of dealing with them. Refrigeration equipment will not bother, given our advice.

Easily removable causes of noise

If a knock is heard in a technique that has worked faithfully for more than one year, the most likely reason the masters call compressor failure.

But if we are talking about a new refrigerator, the problem may lie simply in grinding in new parts or improper operation of the unit. Therefore, before calling a repair technician, make sure that you cannot get rid of the noise yourself.

No. 1 - improper installation or operation

The simplest and most common reason that a working refrigerator makes a knock and other uncharacteristic sounds is not a smooth base.

Even if it seems visually that the device is installed correctly, the check will not hurt, because because of the uneven floor, one of the legs of the unit can only touch the surface, or even just hang in the air. This makes the whole housing vibrate when the engine is running.

To check the evenness, you can use the horizontal building level, putting it on the "roof" of the unit. A simple plumb line of a strong thread and a small weight, such as a nut, will help replace the tool.

Setting the refrigerator by level
Almost all modern refrigerators are equipped with height-adjustable legs on the thread, with which you can correctly set the level

Another source of sound may be a compressor in contact with other metal parts when skewed. Also, pipes bent during transportation of the device may emit a knock. In this case, you need to carefully bend the elements or put rubber pads to eliminate contact.

If the refrigerator has been working for a long time and suddenly began to make various noises, first check the temperature inside its chambers. Does the device freeze properly, and nothing force majeure, except for unusual knocks and rattles, was found?

Perhaps the reason for the increased noise lies in overloaded shelves or in the arrangement of the products themselves - pots, cans and other hard containers can touch and knock on each other when starting or turning off the motor.

Try to completely free the unit from stocks placed inside it, including items on the roof of the case. If the noise has disappeared - the issue is resolved.

Flatness of the internal shelves
The reason for incomprehensible sounds during the operation of the refrigerator may be unevenly installed or insufficiently tightly fixed shelves inside the unit - they also need to be checked for horizontal / vertical

But if during inspection other malfunctions are found, for example, broken lights, snow or obvious “shortage” of temperature indicators, most likely, it will be necessary to inspect and replace failed parts.

No. 2 - loose compressor mount

If the refrigerator has just “moved” to your place of permanent residence, make sure that the transportation bolts or other fasteners that secure the compressor are removed before switching on.

However, such protection is not provided for all models, so it is not out of place to look at the instructions and study recommendations about the first start of the refrigerator.

Compressor Shipping Bolts
By means of transport bolts, the compressor is firmly fixed to the housing, so as not to shake the pipe or the refrigerator case

If the situation is the opposite - the refrigerator has long been working in a constant place and suddenly began to knock, perhaps the mounting hardware that holds the compressor has loosened, or the rubber gaskets are worn out.

Such a problem is not uncommon for older models where springs are used, and if the compressor is skewed, when turned on / off, its casing will knock on the case, rocking the refrigerator. Repair measures here are simple - the springs should be tightened or replaced, the bolts tightened, the gaskets updated.

Compressor mountings
To make sure that the noise source lies precisely in the loose mounts, just put your hand on a running motor, and if the knock stops, try tightening the mounting screws

To align the position of the suspension, you need:

  1. Unscrew the fixing screws and dismantle the condenser - this is if it interferes with the inspection of the compressor.
  2. Check the annular gap between the rubber sleeve of the frame and the support of the casing - it should be uniform.
  3. If a discrepancy is found, unscrew the screws securing the springs to the frame half a turn and adjust the degree of tension to achieve the same clearance around the entire perimeter of the part.
  4. After that, you can turn on the device, check its position by slightly swaying, and if everything is in order, reinstall the capacitor.

A knock may appear due to an object stuck behind the condenser tubes located on the rear wall of the unit, because for many owners the roof of the device is used as a convenient shelf for storing all kinds of small things.

Therefore, carefully inspect the elements, and if a foreign element is detected - remove, but at the same time, and check whether the tubes are in contact with the refrigerator body.

Failure of individual parts

In addition to improper installation and other easily fixed problems, knocking or clicking in the refrigerator can signal a malfunction in its component parts.

And although the deteriorated compressor is recognized as the leader in breakdowns, other details of the refrigerator can also be a source of incomprehensible sounds. Consider the most common fault options.

Breakdown # 1 - Fan Malfunction

If a layer of frost freezes in the fan area, the spinning blades will touch the ice, and the refrigerator will make various clicks and rattle. When snow or pieces of ice get from a frozen evaporator, there is also a knock.

The internal structure of the refrigerator
If there is insufficient air circulation, the fan wheel will rotate continuously to minimize the temperature level in the refrigerator compartment.

There may be several reasons for the increased production of snow.

Improper temperature setting. To speed up the freezing of products or to cook dishes with gelatin, mistresses often switch the cooling control to the maximum, and then forget to transfer to the medium mark.

Inadequate ventilation. If the room is too hot, for example, in the summer season or with active cooking, when both the stove and the oven work. Either the appliance is too close to a wall or a radiator, the compressor will run continuously, forcing cold.

Leaky door. At the refrigerator, especially the old one, the seal is drying up over time or containers with products do not allow to completely isolate it from the external environment.

In any case, if warm air continuously enters the device from the room, ice will quickly appear on the heater, and the motor will run to wear, trying to achieve the required temperature values.

Evaporator Failure. Such a breakdown is often found in models NoFrost refrigerators. And when the evaporator is covered with ice, air stops circulating, forcing the fans to work continuously.

The first action is completely defrost the appliance (at least 10 hours), check the set temperature, the tightness of the door, ventilation gaps. In addition, it does not hurt to renew the grease in the fan bearings - it dries out over time.

It is also worth checking the condition of the winding of the impeller electric motor - during prolonged uninterrupted operation, it may burn out and require replacement. And only after that reconnect the unit to the mains.

Refrigerator Information Display
Modern refrigerators have a display on the control panel, which displays information about the temperature in various compartments of the device, and when a breakdown occurs, a hint with an error code is displayed

If the noise disappears, but appears again after a few days, the problem is most likely in the icy evaporator. And to inspect the part, you need to remove the inner panel in the back wall of the refrigerator, which protects its structural elements.

The nuances of disassembly should be indicated in the instructions. But also the cause of the problem could be refrigerant leakage or clogging of the capillary tube. In the first case, it is necessary to determine the place of damage to the pipeline through which the working medium circulates, solder it and fill with freon.

In the second, you need to clean the channel designed for condensate to drain into the receiver organized for it. Cleaning is carried out mechanically using the device available in the majority of drip refrigerators, or by washing using household chemicals.

Ice on TEN
Snow coat, ice on the back of the refrigerator or its parts is a signal that should not be ignored, because it can lead to serious damage

If this does not help, it is better to turn off the device and call the wizard for diagnostics. If the refrigerator continues to work, the compressor or fan may fail, and repairs will cost several times more.

Failure # 2 - motor-compressor malfunction

The heart of the refrigerator is hidden on the back of the appliance.The compressor's task is to pressurize so that the vaporous refrigerant enters the condenser, cooling the chambers.

Then, heating the freon turns into a liquid, enters the evaporator and again returns to the starting point. If any malfunction breaks this cycle, the refrigerator will not freeze.

Refrigerator compressor
The most common motor compressors are oil, they visually represent a small metal tank, painted black

If the compressor breaks down, clicks and knocks will be heard - this starting relay unsuccessfully trying to start the engine. In this case, it is better to turn off the refrigerator before repairing or replacing a worn part.

True, most masters do not undertake to disassemble and repair a dead compressor, but they will immediately recommend changing it to a similar model. After all, even if it is possible to reanimate the motor, it can break again at any time.

If everything is not so obvious, and the device works, but with interruptions, clicks and knocking, failure of the motor bearings or wear of the cylinder seal can occur. But since the engine with the compressor is enclosed in a sealed enclosure, they do not disassemble it, but simply replace the device with a new one.

Compressor replacement
It is quite difficult to carry out such repairs on your own, because in addition to the appropriate skills, professional tools will also be needed: an oxygen-propane burner, a refrigerant storage and a piercing valve

Replace as follows:

  1. The refrigerator is disconnected from the network, freed from food and thawed.
  2. The compressor needs to be extended, lifted and broken into the filling tube. Then the engine starts for a few minutes so that the refrigerant is completely transferred to the condenser.
  3. Now, with the help of a piercing valve, the hose of the sampling cylinder is connected and gas is collected. The substance is explosive, therefore work is recommended to be carried out with an open window.
  4. The filling tube is replaced by a copper one and soldered with a torch, and if not, with a soldering iron.
  5. Then you need to make an incision in a couple of centimeters on the capillary expander, break off the tube with nippers and solder the filter from the condenser.
  6. After that, the compressor is completely disconnected from other pipes and the housing itself. Typically, there are two tubes - for removing excess gas and forcing pressure.

It remains to replace the new heart of the refrigerator, repeat the steps in the reverse order and carry out a test run.

Knock Prevention Tips

In order for the device to work without unnecessary acoustic accompaniment, do not ignore the rules of its operation and installation recommendations.

Take the time to check the levelness of the floor in the place under the refrigerator. In advanced cases, it is easier to use a strong substrate than trying to align the position with legs.

Foot height adjustment
For the refrigerator door to close independently by the principle of an automatic closer, raise the front legs to a height of 1-1.5 cm

Practical tips:

  1. Determine the correct place for the refrigerator - with a minimum distance of 50 cm from the battery, oven and stove. It is also undesirable for direct sunlight to fall on the unit from the window - there is no need for additional heating of the case.
  2. Between the wall and the rear wall of the device, a gap of at least 10 cm is required.
  3. Do not use the appliance lid as a storehouse for various items and do not try to install a microwave on such a convenient shelf - such “neighbors” significantly reduce the life of the unit.
  4. Adjust the internal shelves and drawers according to the level to a height convenient for you and correctly distribute the products and containers inside the chambers.
  5. Do not turn on for a long time modes with fast freezing and the lowest possible cooling temperature, especially in the hot season.

And the last obvious, but so rarely performed advice - defrost your refrigerator on time, without waiting for abundant snow growths and ice.

If the measures to eliminate knocking did not lead to the desired result, the cause of the malfunction is a serious breakdown. How to repair the refrigerator is described in detail in next article. We recommend useful information to both independent home craftsmen and customers of the services of craftsmen from service centers to control the work.

Conclusions and useful video on the topic

In order to understand in more detail the sound representation that a refrigerator can arrange and eliminate possible breakdowns, we suggest studying our selection of video materials.

What sounds can a refrigerator make?

What to do if an unnatural noise is heard from the device:

Dismantling and repair of refrigeration units with NoFrost system:

How to replace a failed compressor with your own hands:

If you are poorly guided in the device of the refrigerator, and simple methods for eliminating possible problems did not help to cope with extraneous sounds, it is better to call the repair technician. This will cost less than independent experiments.

Want to talk about your own experience in eliminating the knock of the refrigerator? Do you have useful information on the topic of the article, which is worth sharing with site visitors? Please write comments in the block below, post pictures, ask questions about controversial or interested points.

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Visitors Comments
  1. Sergei

    When it comes to the knocking of the refrigerator, I immediately remember the immortal film “Ivan Vasilievich ...”, where the refrigerator knocked because a cat came up to its back wall and began to itch. We had a similar case, though not so anecdotal. For a long time, when the refrigerator was working, a strange tapping appeared periodically ... until they found out that it was a neighbor who put a workbench behind the wall and periodically made something. And then the masters were about to call, since they themselves could not find the reason, and the refrigerator was recently purchased.

  2. Our old refrigerator began to knock and rattle - they thought something had broken. It turned out that just the legs warped over time. When corrected, continued to work normally.
    In general, as I understood from what I read, most of the problems with the refrigerator can be solved independently without calling the wizard. The main thing is to have the right tools and parts.

  3. Karina

    We once bought an Ariston refrigerator for a good deal. Rejoiced exactly until the moment it turned on. He worked very noisily and knocked periodically. I called the master from the service center to measure the noise level of the refrigerator. It turns out that the permissible noise of the refrigerator is up to 42 dB, and we had 39 dB. And no one began to bother with this problem. I had to close the doors to the kitchen tightly before going to bed. At the next purchase, we first of all paid attention to the noise level of the chosen model.

  4. Michael

    I fixed the knock myself, but what to do with the buzz? Sometimes it feels like it will explode.

    • Expert
      Evgenia Kravchenko

      Hello. The refrigerator may be humming for various reasons, including:

      1. Natural buzz, as in the old models of Soviet-made refrigerators.
      2.The close location of the back of the refrigerator (for example, close to the wall), by the way, is often combined with a knock.
      3. Installation distortions.
      4. Problems with the fan due to dried grease, problems with the heater, temperature differences, freezing, etc.
      5. Burnt refrigerator parts.

      Describe the problem in more detail in the comments and name the model of the refrigerator, try to help you.

  5. Tamara

    We bought Samsung, a month later it began - they thought that someone was throwing stones, it turned out that these sounds were behind the refrigerator. Already the third year. They even thought that the brownie was attached to the refrigerator. The refrigerator itself is working standards, but these sounds of "stoning" do not stop ...

    • Expert
      Evgenia Kravchenko

      Hello. Tamara, please describe your problem in more detail. In particular, under what circumstances there is a knock (with the compressor running or in rest mode), and also name the model of your Samsung refrigerator. We will be happy to help you.

      In the meantime, I will try to describe the most common reasons that lead to the fact that the refrigerator can make clicking (cracking) sounds:

      1. The first reason is the incorrectly adjusted springs of the motor-compressor.
      2. The capacitor may resonate, as a result of which a corresponding crackling or clicking sound appears, which is transmitted by vibration to neighboring parts.
      3. It is possible that plastic elements emit crackling sound.

      I have only one question: why do you endure these unpleasant sounds for three years? One call from a qualified technician can solve this problem.

  6. Igor S

    Hello. I have a built-in refrigerator without a freezer. He is only half a year old. He began to knock. The sound is like knocking on a door. About 10 beats with an interval of about a second. Then 30 minutes it works quietly. The temperature inside is normal. What could it be?

    • Expert
      Evgenia Kravchenko

      Hello. In order for us to help you, please specify the model of your refrigerator and its location, and we will answer your question ourselves or contact the manufacturer’s service center and ask them this question.

      P.S. Also specify at what point the knock begins (when turned on, before turning off, in the middle of work).

  7. Tatyana

    Leran refrigerator, purchased 2 weeks ago. Now there is a sound in the back of the refrigerator in the middle - a single click (like a stone in a window). It happens both when the refrigerator is working and not. Even when I turned off the network there was a single click. It is worth the level, the motor is in order.

    • Expert
      Evgenia Kravchenko

      Hello. Please indicate the model of the refrigerator. But in general, if the refrigerator freezes and cools as it should, if there is no water under it and there is no burning smell, malfunctions of the device, strange noise and no error code on the electronic display - this is not necessarily a breakdown, but there may well be a normal reaction to the temperature impact. Many refrigerators sometimes tap.

      In any case, we recommend that you contact the service center by contact phone and ask a question there. Your warranty has not expired and you should not repair the device yourself.

  8. Elizabeth

    Hello, I want to share my story. For a week, the refrigerator was knocking on the back wall, as if they were throwing small stones, before that everything was fine.

    They called the master, said that it is possible to leak freon, but to fill up freon and find the leak is expensive, it is easier to buy a new refrigerator. The master also advised to adjust the temperature in the refrigerator (we had a little more than 4). In general, the refrigerator was defrosted - it was about 20 minutes, then it was turned on and set to 1, and that’s it: the refrigerator stopped knocking. I hope this is useful to someone.

    Refrigerator Eyelid with drip system

  9. Elizara

    Hello.The refrigerator is knocking, what should I do? The knock is as if pebbles are thrown on the sides of the refrigerator.