An unexpected loud crackling sound coming from a refrigerator cabinet can scare any owner of household appliances, especially if the sound occurs at night or in silence. Often this sound resembles gunshots, impacts or sharp friction of metal, which instantly raises alarm about the safety of food and the serviceability of expensive equipment. In most cases, such acoustic effects do not pose a critical threat, but they cannot be completely ignored, since they can signal problems in the operation of of the compressor group or the refrigerant circulation system.
The nature of noise can be completely different: from the banal expansion of materials when the temperature changes to serious mechanical damage to the internal components of the unit. It is important to understand that modern models of refrigerators, especially systems No Frosthave a complex operating cycle, including periods of active cooling and automatic defrosting. It is temperature changes and the operation of various mechanisms that most often become the source of extraneous sounds, which the user mistakes for a breakdown.
In this article, we will analyze in detail the main reasons why a refrigerator cracks, divide them into safe ones and those requiring the intervention of a specialist, and also provide a step-by-step diagnostic algorithm. You will learn how to distinguish normal operating noise from a sign of malfunction, and in which cases you need to immediately contact a service center to prevent more serious damage.
Physics of the process: thermal expansion of materials
The most common and absolutely safe cause of cracking is thermal expansion and contraction of materials. The internal plastic lining of the chamber, metal evaporators and even the outer walls of the housing are constantly exposed to changing temperatures. When the compressor turns on and begins to cool the space, the materials sharply compress, and when it stops, they expand, producing characteristic clicks or crackling sounds.
This effect is especially often observed in refrigerators with a system No Frostwhere defrost cycles occur regularly. The plastic from which the internal drawers and shelves are made reacts to temperature changes faster than metal, creating stress at the attachment points. If you hear a crackling sound immediately after turning the unit on or off, then with a 90% probability this is the physics of the process and not a breakdown.
⚠️ Attention: If the crackling sound is accompanied by the smell of burnt wiring or visible smoke, immediately unplug the refrigerator from the network. Thermal expansion should not be accompanied by foreign odors.
The intensity of such sounds may depend on the quality of the plastic and the assembly of a particular model. Cheap plastics can crack louder and more often than high-quality engineered polymers. Over time, as the material ages, the frequency of the sounds may change, but they usually become quieter as the material adapts to constant heating and cooling cycles.
Problems with the compressor and start relay
The compressor is the heart of the refrigerator, and it is the one that creates the main pressure in the system. If you hear a loud metallic cracking or clanging sound when the engine starts, this may indicate a problem with the start relay or the compressor itself. The start relay is responsible for starting the engine, and if its contacts are burnt or the mechanism is stuck, a characteristic sound similar to a crackling or buzzing occurs.
In more serious cases, a cracking sound may indicate mechanical wear on the internal parts of the compressor. The piston group may wear out, the valves may knock, and the bearings may hum. If the sound comes directly from the motor located in the lower rear part of the refrigerator and is of a constant metallic nature, this is an alarming signal.
Diagnostics of the compressor requires caution. A faulty compressor may overheat, which will lead to its complete failure. It is important to listen: if the crackling sound is replaced by a hum, and then the refrigerator goes silent and does not cool, it means that the thermal protection has tripped due to the impossibility of starting.
Experts often call this sound the “shooting” of the compressor. This happens when the pressure in the system does not have time to equalize between starts, or when the refrigerant is in the wrong state (for example, it entered the compressor cylinder in liquid form, which is called water hammer).
Malfunctions of the defrost system (Defrost)
In refrigerators with an automatic defrosting system, a crackling sound is often associated with the operation of the defrost heating element or timer. When the defrost cycle begins, the heating element begins to heat the evaporator to melt the frost. The sudden heating of cold metal causes a strong cracking sound, which can be heard throughout the entire body.
In addition, the defrost system may contain a valve that regulates the supply of refrigerant. If this valve is faulty or dirty, it may make a clicking sound when trying to shift. It is also worth mentioning the possible freezing of the fan in the system No Frost: if ice builds up on the blades, the fan begins to crack, touching ice pieces.
☑️ Diagnostics of the defrost system
It is important to distinguish a normal defrosting sound from an abnormal one. The normal cracking sound lasts a few minutes at the beginning of the defrost cycle. If the cracking continues for a long time or is accompanied by a lack of cooling, the heating element may have overheated or the defrost thermostat has failed.
Sometimes the defrost system uses a special valve that can click. If this click becomes a loud crack, there may be an air lock in the system or the circulation of freon is disrupted, which requires the intervention of a technician to refill or vacuum the system.
Vibration and contact with foreign objects
Often a loud crack or rattling is caused not by internal breakdowns, but by external vibration. If the refrigerator is not level, its legs are not adjusted, or it touches a wall, cabinet or other piece of furniture, the running compressor causes the entire cabinet to vibrate. This vibration is transmitted to objects, causing a resonating crackling sound.
Check the area around the refrigerator. Is there enough clearance between the back wall and the wall? Are the shelves inside touching each other or the walls of the chamber? Even one poorly placed glass on the top shelf can become a source of strong noise due to resonance.
It is also worth inspecting the back of the refrigerator, where the compressor is located. There is a tray for collecting condensate. If it is loose or misaligned, vibration from the motor will cause it to rattle. Cooling system tubes can behave similarly if they come into contact with each other or with the housing wall without damping gaskets.
How to check the evenness of the installation?
Place a glass of water on the top shelf of the refrigerator. If the surface of the water oscillates or tilts, the refrigerator is not level. Adjust the front legs until the water becomes calm and the door begins to slam shut when slightly opened.
Evaporator defects and refrigerant circulation
Sometimes a cracking sound inside the refrigerator or freezer can be associated with the circulation of refrigerant through the pipes evaporator. If a plug has formed in the system or the flow of freon is disrupted, sounds resembling gurgling or sharp clicks may occur. However, more often this is still due to the thermal expansion of the evaporator itself.
In the freezer, where temperatures are extremely low, the metal contracts more strongly. If the evaporator design has defects in soldering or fastening, this can lead to microshifts and a characteristic crackling sound. In systems No Frost ice that builds up on the evaporator can also crack when chipping or falling on heating elements.
| Type of sound | Probable cause | Danger | Actions |
|---|---|---|---|
| Rare clicks | Thermal expansion | No | Observe |
| Loud clanging at start | Start relay / Compressor | High | Call a technician |
| Constant crackling inside | Fan / Ice | Average | Defrost |
| Casing rattling | Vibration / Feet | No | Align |
If the crackling comes from inside the chamber and is accompanied the appearance of a large amount of ice or, conversely, insufficient cooling, this may indicate a freon leak or a clogged capillary tube. In such cases, the system operates in emergency mode, trying to compensate for the lack of refrigerant, which causes pressure drops and sounds.
Self-diagnosis algorithm
Before calling a technician, try to carry out the initial diagnosis yourself. This will help you more accurately describe the problem to a specialist or, perhaps, solve it without extra costs. Start with a visual inspection and listening to the unit in different operating modes.
The first step is to eliminate external factors: check the stability of the refrigerator, the absence of contact with furniture and foreign objects inside. Then listen to the timing of the compressor turning on and off. If the crackling sound is associated only with these moments, most likely it is a matter of thermal expansion.
If the refrigerator is equipped with a system No Frost, try defrosting it. Complete defrosting within 24 hours will melt the ice on the evaporator and fan. If the cracking noise disappears after switching on, then the problem was in freezing of the defrosting system.
⚠️ Attention: When defrosting, do not use sharp objects to chip ice and do not use hair dryers or heaters to speed up the process. This can damage the thin tubes of the evaporator, which will lead to expensive repairs.
If simple methods do not help, and the sound becomes louder or its character changes, you need to contact a professional. Independent repair of complex components, such as a compressor or circulation system, requires special equipment and knowledge.
When you need to call a specialist
There are a number of signs in which independent actions are useless and even dangerous. If the cracking sound is accompanied by a lack of cold, the appearance of a “coat” of ice in one corner, or, conversely, complete defrosting of the food, this indicates a technical malfunction.
Also a reason to call a specialist is the situation when the compressor tries to start, makes a loud cracking or clicking sound, and then goes out, and this is repeated several times. This indicates a malfunction of the starting equipment or the motor itself, which requires replacement of parts.
You should not ignore the burning smell that can accompany a crackling sound. This is a sure sign of electrical failure, overheating of the wiring or insulation. In this case, operation of the refrigerator must be stopped until the cause is eliminated.
Remember that modern refrigerators are complex devices where mechanical, electrical and electronic components are closely interconnected. Correct diagnosis requires experience and tools, so in doubtful cases it is better to trust professionals.
Is it possible to use a refrigerator if it is cracking?
If the cracking is caused by thermal expansion or vibration, it is possible. If the crackling sound is associated with the compressor (metallic clanging, inability to start), operation will lead to engine combustion. If there is a burning smell, use is prohibited.
Preventing noise and extending service life
To minimize the risks of extraneous sounds and damage, it is important to install the refrigerator correctly from the very beginning. A flat surface, no direct contact with the walls and compliance with the temperature regime around the unit are the key to quiet operation.
Regular defrosting (even for systems No Frost it is recommended to do this once a year) will help to avoid ice fouling of internal mechanisms. Keep the condenser at the back of the refrigerator clean: dust and animal hair impair heat transfer, causing the compressor to work harder and noisier.
Do not overload the shelves and make sure that food does not touch the back wall of the chamber. This will not only prevent rattling noises from vibration, but will also ensure proper air circulation, which is important for uniform cooling and maintaining food freshness.
Caring for door seals is also important. If the door does not close tightly, warm, moist air enters the chamber, which leads to increased ice formation and more frequent compressor cycles, increasing the overall noise level.
Why does the refrigerator only crack at night?
At night, the apartment is quieter, and background noise is reduced, so the sounds of appliances become more noticeable. In addition, the mains voltage may drop at night, which makes it difficult for the compressor to start and causes louder sounds when trying to start. Also, at night, the defrost cycle starts more often if the refrigerator is set to certain operating hours.
Is it dangerous if the refrigerator is cracking and does not freeze?
Yes, this is a critical situation. The combination of noise and lack of cold indicates that the compressor is running empty or not working at all, or there is a refrigerant leak. Products may deteriorate, and further operation of the motor without load or with overheating will lead to its combustion.
Can a new refrigerator crack?
Yes, new refrigerators can make sounds due to shrinkage of materials, primary expansion of plastic and metal. Also, in new models, the shipping bolts may be slightly loose (if you forgot to remove them) or the packaging elements inside. Usually, after a few days of operation, the sounds subside.
How to distinguish the crackling of a compressor from the crackling of plastic?
The crackling of plastic is usually louder, shorter and confined to moments of temperature change (on/off). The compressor crackling sound is more dull, metallic, often accompanied by vibration of the housing and occurs in the lower part of the unit. The plastic cracks chaotically, the compressor cracks rhythmically or at the moment of load.