A sudden loud bang or periodic crackling sound in a working refrigerator can scare any owner. Refrigeration equipment normally it should work quietly, emitting only a subtle hum, so any extraneous sounds are perceived as an alarm signal. If something is banging in your unit, it is important not to panic, but to consistently analyze the nature of the sound and the conditions for its occurrence.
Most often, the reason lies in natural physical processes, such as thermal expansion of materials or the operation of the defrost system, but sometimes this indicates a serious breakdown compressor or electrical. Understanding the difference between normal noise and an alarm signal will help you make the right decision: continue operation or call a repairman.
In this article we will analyze in detail all the possible reasons why the refrigerator is banging, from harmless plastic clicks to critical engine malfunctions. You will learn how to carry out initial diagnostics on your own and in which cases independent repair is impossible.
Natural sounds: thermal expansion of plastic and metal
The most common reason why something bangs or cracks in the refrigerator is a change in the temperature of the internal materials. The walls of the chamber, shelves and evaporator are cooled during operation, and when the compressor stops or during the defrost cycle they heat up. Thermal expansion causes a displacement of layers of plastic and metal, which is accompanied by a characteristic crackling sound or single clicks.
This process is especially loud in new models or after loading a large amount of warm food. The internal liner (plastic lining) can react to temperature changes quite sharply, making sounds similar to gunshots. Typically, such sounds do not pose any threat to equipment and go away on their own after some time after the temperature has stabilized.
The intensity of the sounds depends on the quality of the plastic and the design of the evaporator. In budget models or devices with the system No Frost this effect can be more pronounced due to the assembly features and materials used. If the sound is heard exclusively when the engine is turned on or off, then this is normal.
⚠️ Attention: If the crackling sound is accompanied by a burning smell or smoke, immediately unplug the device. Unlike thermal expansion, a smell indicates overheating of wiring or insulation.
It is important to note that in models with No Frost sounds may be louder due to the presence of additional fans and a more complex air circulation system. The plastic here works as a resonator, enhancing the natural noise of the operating unit. Over time, when the equipment “gets used to”, the frequency of such pops usually decreases.
Operation of the automatic defrosting system
If your refrigerator is equipped system No Frost or Full No Frost, then periodic popping noises may be associated with the evaporator defrost cycle. In this mode, a special heating element (Heating element) is turned on according to a timer to melt the ice on the radiator. Sharp heating of cold metal often causes a sound effect similar to a lumbago or a loud crack.
In addition, melting water drips onto a hot heating element or into a pan, which can be accompanied by hissing and short explosive sounds of steam. This is an absolutely normal situation for modern technology. Cyclicity Such sounds (for example, once every 8-12 hours) are a sure sign that the defrosting system is working properly.
Sometimes ice accumulated on the evaporator can break off in large pieces and fall into the lower part of the chamber or onto the fan. A block of ice falling from a height produces a dull thud, which can easily be confused with a break. The fan can also touch the ice crust, making a cracking sound until the ice completely melts.
Why does the ice fall?
The ice crust on the evaporator is formed from moisture contained in the air of the chamber. When the heating element is turned on, the ice melts at the base and falls down under its own weight, creating a shock sound.
It is worth considering that if the defrosting system is faulty, the ice may build up excessively, and then the sounds of falling or cracking will become constant companions of the refrigerator. In this case, it is necessary to check the serviceability of the defrost sensors and timer.
Problems with the compressor and start relay
The situation becomes more serious if there is a knock in the area of the compressor motor located in the lower rear part of the unit. A loud click followed by a hum and then silence (or another click) often indicates problems with starting relay. This device is responsible for starting the engine, and when it wears out or breaks down, the contacts can stick or spark, creating a characteristic pop.
If the compressor tries to start, makes a pop, hums for a few seconds and turns off - this is a sign of a “wedge” of the engine or a malfunction of the starting winding. At this moment, an electric arc may break down inside the relay, which gives a sound and sometimes light effect. It is impossible to operate the equipment in this mode, as this can lead to combustion of the compressor windings.
Sometimes the cause of the pop is itself compressor. If the valves are internally broken or the piston group suspension is destroyed, metallic knocks and impacts may be heard inside the housing. This indicates mechanical destruction of the unit, which requires replacement.
You can diagnose a problem with the motor by temperature: if after the pop the compressor remains cold or, conversely, overheats and does not start, the problem is definitely in the electrical or mechanical part of the engine. In such cases, the intervention of a specialist with appropriate equipment is required.
Faults in electrical wiring and contacts
One of the most dangerous scenarios when something is banging in the refrigerator is a short circuit or insulation breakdown. An electrical discharge is always accompanied by a loud bang, often accompanied by a flash of light and the smell of burning plastic. Most often this happens at the point where the wires are connected to the compressor, thermostat or control unit.
The cause may be oxidation of the contacts, moisture on the terminals, or loose connections. At the moment of a power surge or an attempt to turn on the load, a breakdown of the air gap occurs. Electric arc not only makes a sound, but also melts the plastic, creating a risk of fire.
Particular attention should be paid to the wiring going to the defrost heating element. If the wire insulation is damaged and touches the metal body of the evaporator, when the heating is turned on, a short circuit will occur with a characteristic bang and knocking out plugs in the apartment.
| Sound type | Probable cause | Danger | Actions |
|---|---|---|---|
| Crackling, clicking | Thermal expansion | Safe | Observation |
| Thud | Ice falling | Safe | Checking defrost |
| Click + buzzing | Start relay | Medium | Replacement relay |
| Clap + spark | Short circuit | High | Disconnect from the network |
⚠️ Attention: If you suspect an electrical breakdown (sparking, burning smell), it is strictly forbidden to connect the device to the network until the wiring is fully checked by a technician. This may lead to a fire.
Hydraulic hammer in the cooling system
In rare cases, but still possible, the sound may be caused by the movement of refrigerant through the system pipes. If circulation in the circuit is disrupted or the capillary tube is clogged, freon may move jerkily. When passing through bends or filter-driers under high pressure, an effect similar to water hammer may occur, accompanied by a whistle, hissing or short blows.
The gas itself can also produce a sound when there is a sudden change in pressure, for example, immediately after stopping the compressor, when the pressure in the system equalizes. Usually this is a quiet hissing, but at certain resonant frequencies of the tubes it can increase. Refrigerant In normal condition it should not make loud pops.
If you hear gurgling, turning into sharp blows, this may indicate that air or moisture has entered the system, or the amount of refrigerant is critically low. In such cases, the cooling efficiency drops and the load on the compressor increases.
☑️ Primary sound diagnostics
External factors and incorrect installation
Sometimes the sound source is not inside the refrigerator at all, and is related to the conditions of its operation. If the unit is not level, vibration from the operating compressor is transmitted to the housing and floor, causing rattling and periodic impacts of the legs on the surface. Vibration can lead to the displacement of nearby objects that fall or hit the walls.
Check that they are not touching whether the walls of the refrigerator are furniture or other objects. When the motor is running, the housing may expand or vibrate slightly and contact with an obstacle will cause a knocking noise. It is also worth inspecting the rear grille of the condenser: if it is deformed and touches the tubes or the body, it will ring and bang every time it starts.
The floor on which the refrigerator stands also plays a role. Wood flooring or soft linoleum can enhance resonance. In some cases, the “bang” sound may come from objects that have fallen behind the refrigerator or are on its roof (for example, jars of pickles or decorative items).
How to check the levelness of the installation?
Put a glass of water on the top shelf of the refrigerator. If (the surface of the water) oscillates or is tilted, the equipment must be leveled using the adjustable support legs.
When to call a professional
Although many sounds are safe, there are situations that require professional intervention. If the claps become regular, are accompanied by a loss of cold, the appearance of a smell, or knocking out the machines in the panel, you cannot hesitate. The combination of a loud electric pop with the refrigerator stopping working is a direct signal of a serious malfunction of the electrical circuit.
A technician will be needed if:
- 🔌 The pops come directly from the compressor or control unit.
- 🔥 A persistent smell of burnt insulation or plastic has appeared.
- ❄️ The refrigerator has stopped freezing or is freezing too weakly.
- 💡 At the moment of sound the light in the apartment blinks or the backlight inside the chamber goes out.
- 🔊 The sound is accompanied by sparking visible through the ventilation holes.
Independent repair of live components or a sealed circuit without special equipment and skills is prohibited and life-threatening. Diagnostics of the electrical part requires the use of a multimeter, and checking the compressor requires a manometric manifold.
Why does the refrigerator pop loudly immediately after being plugged in?
A loud pop when turned on for the first time often indicates a breakdown in the compressor start relay or a short circuit in the defrost heating element circuit. At this moment the maximum current surge occurs. If the relay is faulty, the contacts may weld or rupture with a spark. It is also possible that a short circuit has already occurred in the system, and when voltage is applied, the protection is triggered.
Can ice in the freezer make gunshot sounds?
Yes, it can. With the system No Frost ice accumulates on the evaporator hidden. When the heater is turned on, massive pieces of ice, thawing at the base, can suddenly fall down. The fall of a heavy block of ice onto a metal bottom or plastic parts creates a dull but powerful impact that can easily be confused with a gunshot. This is the physical sound of a solid body falling.
Is it dangerous if plastic cracks in the refrigerator?
The cracking of plastic caused by thermal expansion is absolutely safe for equipment and humans. This is a physical feature of polymer materials that change their geometric dimensions with temperature changes. However, if the cracking sound is very loud and constant, it is worth checking whether the inner box is deformed due to overheating or a manufacturing defect, which happens extremely rarely.
What to do if the refrigerator stops working after the bang?
You must immediately unplug the cord from the outlet. Do not try to turn it on again “to check”. Most likely, the start relay has burned out, the compressor winding has broken, or the control module has burned out. Turning it on again can finish off the surviving nodes or cause a fire. Call a technician for diagnostics.