When faced with extraneous noise emanating from kitchen appliances, many owners immediately begin to panic, expecting expensive repairs or complete replacement unit. However, it does not always crackling in the refrigerator indicate a critical malfunction of internal components or the electrical system. In some cases, this is a natural physical process associated with changes in temperature conditions and the properties of the materials from which the body and inner chamber are made.
Understanding the nature of sounds allows you to save significant money on calling a technician and avoid unnecessary stress. It is important to learn to distinguish normal operating noise from signals that require immediate intervention. The volume, frequency and nature of the sound play a decisive role in the initial diagnosis of the condition of your household appliance.
In this article we will analyze in detail all the possible reasons why the refrigerator clicks or crackles, consider the design of the defrost system and compressor, and also provide a step-by-step algorithm for actions when anomalies are detected. You will learn to independently determine whether the sound is a sign of a breakdown or the normal operation of the equipment.
Physics of the process: thermal expansion of materials
The most common reason why a refrigerator makes clicks and crackles is banal thermal expansion. The inner walls of the chamber, plastic shelves and cladding elements are made of polymers that change their volume with a sharp temperature change. When the compressor starts and begins to pump in cold, or vice versa, when a defrost cycle occurs, the temperature of the surfaces changes.
This process is accompanied by a characteristic sound, reminiscent of the crackling of plastic or the bursting of bubbles. Such sounds are especially often heard in new models or after defrosting, when temperature contrasts are highest. Thermal expansion This is an absolutely normal physical phenomenon that does not require any repair.
- 🔹 The crackling noise is heard irregularly, most often immediately after turning on or off motor.
- 🔹 The sound comes from the walls of the chamber or the outer casing, and not from the depths of the unit.
- 🔹 The intensity of the noise gradually decreases as the temperature inside stabilizes.
It is worth noting that in modern models with the system No Frost the number of plastic elements inside the structure is much higher than in old “crying” refrigerators. Therefore, owners of new equipment may hear such sounds more often. If the cracking sound is not accompanied by loss of cold or other abnormalities, there is nothing to worry about.
⚠️ Attention: If the cracking sound is accompanied by the smell of burning or melted plastic, immediately unplug the device. This may indicate overheating of the wiring or an electrical arc, which creates a risk of fire.
Operation of the automatic defrost system
In refrigerators equipped with system No Frost, the process of automatic defrosting of the evaporator occurs regularly. For this, a special heating element is used, which is turned on by a timer. When the heating element is turned on or off, as well as during the process of ice melting, various sounds may occur, including gurgling, hissing and a characteristic crackling sound.
The ice accumulated on the evaporator, when suddenly heated, begins to quickly turn into a gaseous state or flow into the drainage system, creating noise. It is also possible that the tubes collapse or the ice crust deforms, which is heard as a loud crack. This is the normal operating mode provided for by the design.
The frequency of such sounds depends on the defrost timer settings and the intensity of use of the refrigerator. Typically the defrost cycle runs several times a day. If you hear a cracking sound at approximately the same time of day or at regular intervals, most likely it is the defrost system.
How does a defrost timer work?
A defrost timer is a mechanical or electronic device that counts down the operating time of the compressor. After dialing a certain number of hours (usually 8-16 hours), it switches the circuit, turning off the compressor and turning on the evaporator heater for 15-30 minutes.
It is important to monitor the condition of the drain hole. If it is clogged, the water can stagnate and, when it refreezes, create ice plugs that, as they expand, will make louder and more unpleasant sounds. Regular preventive maintenance will help avoid problems with drainage.
Faults in the start relay and compressor
The situation changes dramatically if a cracking sound is heard in the lower part of the refrigerator, where the motor-compressor is located, and is accompanied by problems with starting. In this case, the most likely cause is a malfunction starting relay. This device is responsible for supplying current to the motor windings at the time of start.
If the relay fails, the contacts inside it may burn or stick, which causes a characteristic loud click, followed by an attempt to start the motor, and then a second click and shutdown. This cycle can be repeated several times until the thermal relay finally turns off the power to protect the engine from combustion.
- 🔸 A loud metallic click in the compressor area.
- 🔸 The motor hums for several seconds, but does not start.
- 🔸 A repeating cycle is heard “click-buzz-click.”
In such cases, the refrigerator cannot be operated, as the food will begin to defrost. The start relay needs to be replaced, which is a relatively inexpensive and quick procedure for a specialist. However, if you ignore these symptoms, you can lead to the combustion of the compressor itself, the replacement of which is not economically feasible.
⚠️ Attention: Do not try to disassemble the compressor or change the relay yourself if you do not have the skills to work with electricity. Residual voltage and refrigerant inside the system are dangerous.
Problems with the fan in the No Frost system
Another source of noise in refrigerators with the system No Frost is the fan that circulates cold air. If the fan blades become contaminated with dust or ice frozen on them, a cracking, humming, or knocking noise may occur. Ice often forms due to a door that is not tightly closed or a faulty seal.
Rotating blades can touch ice or foreign objects caught in the air duct. This creates an intermittent crackling noise that gets louder when the fan is running. In some models, the fan can stop when the door is opened, which allows you to localize the source of the sound.
To fix the problem, it is often enough to defrost the refrigerator for 24 hours so that the ice in the air circulation system completely melts. If after defrosting the sound returns after a short time, the fan motor itself may be faulty or the geometry of its blades is broken.
| Sound type | Probable cause | Localization | Need for repair |
|---|---|---|---|
| Rare crackling | Thermal expansion | Chamber walls | Not required |
| Loud click + humming | Start relay | Bottom, rear | Replacement required |
| Constant crackling/humming | Fan | Inside, rear wall | Cleaning or replacement |
| Gurgling | Refrigerant in the tubes | All over the body | Normal |
The influence of improper installation on the noise level
Often the cause of extraneous sounds is not an internal breakdown, but an incorrect installation of the unit. If the refrigerator is not level, vibrations from the operating compressor are transmitted to the housing and intensified, causing rattling and cracking of the contacting parts. Vibration can also be transmitted to nearby objects.
It is necessary to check the horizontal installation using a building level. Height adjustment is carried out by twisting or unscrewing the front support legs. Correct installation ensures that the doors will close by themselves when opened slightly, which is also important for tightness.
☑️ Diagnosis of refrigerator installation
In addition, check whether the internal shelves or products are touching the walls of the refrigerator. The vibration can be transferred to glass shelves or plastic containers, which in turn begin to resonate and make a cracking sound. Simply moving food away or adjusting a shelf is enough to eliminate the noise.
When you need to call a professional
Despite the fact that many sounds are safe, there are situations where delay can cost you your refrigerator. If the cracking sound is accompanied by a complete lack of cold, continuous operation of the compressor without stopping, or the appearance of ice in unexpected places, these are signs of a serious malfunction.
Freon leak or a blockage of the capillary system is often masked by strange sounds of the motor, which is trying to compensate for the lack of pressure. In such cases, independent repair is impossible and special equipment is required for diagnostics and refilling.
- 🚨 The refrigerator has stopped freezing or the temperature has increased.
- 🚨 The compressor works without interruption, overheating.
- 🚨 A persistent smell of chemicals or burnt insulation has appeared.
It is also worth contacting a specialist if you are not sure about the nature of the sound. Professional diagnostics will take a little time, but will allow you to accurately determine the condition of the unit and prevent sudden spoilage of food.
⚠️ Attention: The design of modern refrigerators is complex and airtight. Opening the circuit without a vacuum pump and pressure gauges will lead to the ingress of moisture and air, which will completely disable the equipment.
Noise prevention and durability of equipment
To minimize the risk of unpleasant sounds and extend the life of the refrigerator, it is important to follow the operating rules. Regular defrosting (even for the No Frost system, a preventive shutdown is recommended once a year) will help avoid the formation of excessive ice, which often causes cracking.
Keep the condenser grill at the back of the refrigerator clean. Dust and pet hair worsen heat transfer, causing the compressor to work harder and longer, which increases the load on the start relay and increases the likelihood of knocking when starting.
How to properly wash the condenser?
Unplug the refrigerator. Carefully move it away from the wall. Use a soft brush or a vacuum cleaner with a narrow attachment to remove dust from the black grille at the back. Do not use water under pressure.
Also, do not overload the refrigerator with food. Excessive load on shelves and doors can lead to deformation of the internal plastic, which will begin to crack when the temperature changes more actively than new ones. Following these simple rules will ensure quiet and stable operation of your equipment for many years.
Is it normal for a new refrigerator to crack in the first days?
Yes, this is absolutely normal. New materials, such as plastic inner chambers and insulation, undergo an initial process of “shrinkage” and adaptation to temperature changes. In the first 3-5 days of operation, the intensity of thermal expansion is maximum, so cracking may be heard more often. Over time, the sound will become quieter or disappear altogether.
Can a crackling sound be a sign of a freon leak?
A freon leak itself rarely produces a crackling sound. However, when the refrigerant becomes low, the compressor tries to work continuously to reach the set temperature. This overloads the start relay, which begins to click in an attempt to start the engine. Thus, cracking may be an indirect sign of loss of system tightness.
Why does the refrigerator crack only at night?
During the day, extraneous household noises (conversations, TV, street) mask the quiet sounds of equipment operation. At night, in silence, even the normal sounds of thermal expansion or rare clicks of the thermostat become clearly audible. If the refrigerator operates quietly during the day, but at night there is a crackling sound, most likely, everything is in order with the equipment, the acoustic background of the room has simply changed.
Is it dangerous to ignore relay clicks?
Ignoring frequent clicks of the start relay is dangerous. If the relay does not start the compressor the first time, it continues to supply current, which leads to heating of the motor windings. This can eventually cause a short circuit, compressor burnout, or even a wiring fire. If there are repeated clicks without starting, it is better to turn off the device and call a technician.