Suddenly appearing loud knock in the refrigerator can throw anyone off balance. This sound is not just annoying, it often signals that there is a malfunction within a complex mechanism that cannot be ignored. If the unit previously worked quietly, but now makes rhythmic beats or hums, this is a direct reason for diagnosis.
The reasons may be trivial, for example, improper installation or contact of the housing with furniture. However, in a number of cases strong knocking indicates critical wear of the compressor components or a violation of the refrigerant circulation. Understanding the nature of sound is the first step to successful repair or proper adjustment of equipment.
In this article we will analyze in detail the mechanical, electrical and operational factors that cause noise. You will learn how to distinguish a normal operating hum from a dangerous knocking noise, and you will understand when you can handle it yourself and when you need to call a technician.
Mechanical reasons: vibration and body position
The most common reason why a refrigerator makes knocking sounds lies in its incorrect location. If the body is skewed or uneven, vibration from the running motor is transmitted to the floor and walls, causing resonance. In this case, compressor may be in good working order, but its operation is accompanied by noise.
Often users forget to remove the shipping bolts or plastic plugs that secure the moving parts during transportation. Also, knocking noise may occur due to the rear grille (condenser) or tubes touching the wall or cabinet. Even the minimum gap of 5-7 centimeters can be violated, which will lead to the transmission of vibration.
⚠️ Attention: If you notice that the refrigerator “walks” on the floor or is tilted, immediately level it. Long-term operation in a skewed state leads to skew of the motor shaft and its breakdown.
To eliminate the problem, you need to check the adjusting feet. They should fit tightly on the floor, ensuring a stable position. If the floor is uneven, use pads under the legs, but not under the body itself.
Compressor malfunctions: when repairs are needed
If everything is in order with the installation, but the knocking persists, the problem may lie in the heart of the refrigerator - compressor. This is an electromechanical pump that drives freon through the system. Over time, internal parts wear out, and the motor begins to operate noisier.
One of the common causes of knocking is a loose starting valve or wear on the motor shaft bearings. In such cases, the sound often resembles metallic clanging or rhythmic knocking as the unit starts and stops. The springs on which it is secured inside the casing may also be damaged. compressor suspension - springs on which it is fixed inside the casing.
If the springs burst or jump off, the metal housing of the motor begins to beat against the walls of the casing with each switching cycle. This creates a very loud and scary knocking noise. Repair in this case requires disassembling the rear panel and replacing the springs or the compressor itself.
- 🔨 Knocking at start: often indicates problems with the starting relay or valves.
- 🔧 Humming during work: may indicate wear of the piston group.
- ⚙️ Vibration of the motor housing: a sign of destruction of the internal engine mount.
Is it possible to change the compressor yourself?
Replacing a compressor is a complex process that requires evacuation of the system and charging with freon. Without special equipment and a license, it is impossible and dangerous.
Problems with refrigerant circulation
Sometimes the knocking does not come from mechanical parts, but from the refrigerant itself. In normal mode, freon circulates through the tubes silently or with a slight gurgle. However, if an air lock has formed in the system or a capillary tube is clogged, the gas flow becomes turbulent.
Air bubbles passing through narrow areas can create characteristic clicks or short blows. This often happens after poor-quality repairs when the system was not properly evacuated. Also, the cause may be clogged filter drier, which stops passing freon evenly.
In some cases, the sound resembles the pouring of sand or small impacts inside the evaporator tubes. This may indicate that the refrigerant is boiling in the wrong place due to a violation of heat exchange. Diagnosing such problems requires connecting pressure gauges.
No Frost system and fan
In refrigerators with a system No Frost the source of noise is often the fan that drives cold air around the chamber. If ice builds up on the blades or a foreign object gets into the mechanism, the fan begins to hum and knock.
A knock can also occur during defrosting. Melt water drips into the pan, and if it is not installed correctly or is deformed, the drops can create noise. But more dangerous is ice, which freezes on the evaporator and interferes with the rotation of the impeller.
When the ice reaches the fan, a loud cracking or knocking sound is heard, after which the fan may stop. This leads to the fact that the cold stops flowing into the chamber, although the compressor continues to work. In such cases, complete defrosting of the refrigerator is required.
| Sound type | Probable cause | Location | Difficulty of repair |
|---|---|---|---|
| Rhythmic knocking | Wear of compressor suspension | Bottom rear | Average |
| Crackling/Rustling | Fan No Frost | Inside the chamber | Low |
| Gurgling/Clicking | Freon circulation | Throughout the entire body | Low |
| Loud clanging | Spring valve | Bottom rear | High |
Influence of loading and internal elements
The source of noise is not always the unit itself. Often users themselves provoke knocking by incorrectly placing products. Glass bottles or jars standing close to each other or to the walls of the refrigerator begin to rattle from the slightest vibration of the shelves.
It is also worth checking the shelves and drawers themselves. If the plastic vegetable bin is not fully seated in the guides, it may vibrate. Glass shelves lying on rubber shock absorbers may, over time, lose the elasticity of their supports, which also leads to rattling.
Pay attention to containers with liquid. If the bottle is not stable, it may fall or roll when the floor vibrates, causing impacts on the walls of the chamber. Proper organization of space helps reduce noise levels.
☑️ Diagnostics of internal noise
When it is necessary to call a specialist
There are situations when independent repairs are impossible or dangerous. If, after leveling the refrigerator and checking the load, the knocking does not stop, there is probably a problem within the technical part. The sound is especially alarming when the motor heats up or the refrigerator refuses to cool.
If you hear a loud metallic knocking sound at startup, which is quickly replaced by silence (the compressor does not start), this may be a sign of a wedge in the engine or a faulty start relay. Prolonged attempts to turn on such a device can lead to burnout of the windings.
⚠️ Attention: Do not try to disassemble the sealed circuit or change the compressor without the skills and equipment. This requires working with gas under pressure and special oils.
Calling a specialist is necessary if you are not confident in your abilities. Professional diagnostics will take less time than experiments that can lead to costly breakdowns. The technician will determine whether it is possible to replace a separate part or whether the unit needs to be replaced.
Noise prevention and durability of equipment
In order for the refrigerator to operate quietly and for a long time, it is important to follow the operating rules. Check regularly to ensure that the unit has not moved out of position. Periodically clean the rear grille of dust, as overheating also affects the operation of the motor and can increase noise.
Do not overload the refrigerator with food. Overcrowded shelves and drawers place additional stress on the structure and can increase vibration. Monitor the condition of the door seals - if they do not fit tightly, the compressor will work more often and more intensively.
Compliance with the temperature regime and the absence of sudden changes in voltage in the network also extend the life of the equipment. Use voltage stabilizers if your network often fluctuates electricity, as this saves the electronics and motor refrigerator.
Is it normal if the refrigerator makes clicking noises?
Yes, periodic clicking sounds can be normal. They often occur due to thermal expansion and contraction of plastic parts of the housing or when the thermostat is triggered. If the clicking does not turn into a loud knock and the refrigerator is cooling, there is no need to worry.
Why does a new refrigerator knock more than an old one?
Modern models often have more powerful compressors and less massive housings, which can make their operation more audible. In addition, new units may require time to “break in” parts. However, strong knocking is not typical for new equipment.
Can a refrigerator knock due to power surges?
Power surges can cause chaotic switching on and off of the compressor, which is accompanied by relay clicks. Constant changes can lead to damage to the starting winding, which will cause knocking and motor failure.
How long can a knocking refrigerator work?
There is no exact time limit. If the compressor suspension is knocking, it can work for months, but risks breaking the pipes. If the piston knocks due to lack of oil, the count goes on in days or hours until the wedge. It’s better not to take risks.
Does the floor level affect the noise of the refrigerator?
Yes, this is one of the main factors. On an uneven floor, the refrigerator wobbles, causing resonance and the body knocking on objects. Installing it on a flat surface and adjusting the legs often completely eliminates the problem.