The appearance of extraneous sounds in household appliances often becomes a cause for serious concern, especially if it concerns such an important unit as a refrigerator. When a device makes strange clicking, humming or cracking noises, owners immediately start looking for answers, fearing costly repairs or complete loss of products. However, noise does not always indicate a critical malfunction that requires immediate intervention from a technician.
The system No Frost, which literally translates as “without frost,” has a fundamentally different device compared to older models with drip defrosting. In such refrigerators, air circulates rather than refrigerant in open evaporators, which gives rise to specific acoustic effects. Understanding the physics of the processes occurring inside the chamber will help you distinguish the normal operation of mechanisms from real breakdowns.
In this article we will analyze in detail why the No Frost refrigerator cracks, when it is worth sounding the alarm, and in which cases it is enough to simply observe the device. You will learn about the role of thermal expansion of materials, the operation of the defrost system, and possible problems with the compressor or fan. Competent diagnostics begins with an analysis of the nature of the sound and the frequency of its occurrence.
Natural physical processes: thermal expansion
The most common and absolutely harmless cause of cracking is a physical phenomenon known as thermal expansion of materials. The inner walls of the chamber, shelves, plastic containers and even the metal body of the evaporator are constantly exposed to temperature changes. When the compressor turns on and begins to pump in cold, the materials compress, and when it stops, they expand.
This process is accompanied by a characteristic sound, which is often described as crackling, clicking or even ringing. This is especially evident in new refrigerators or after a long defrost, when the temperature difference between the switched on unit and the room environment is maximum. The plastic from which the internal panels are made reacts to cold faster than metal, which creates an acoustic effect.
Thermal deformation affects not only plastic, but also metal structural elements. The aluminum evaporator tubes and steel chamber walls also change their geometric dimensions, although to a lesser extent. If your refrigerator makes a cracking sound mainly in the first hours after switching on or immediately after loading a large amount of warm food, most likely this is the case.
⚠️ Attention: If the cracking sound is accompanied by vibration of the case or displacement of the shelves, check the stability of the installation of the refrigerator. An uneven floor can increase resonance from the natural expansion of materials.
The intensity of such sounds may vary depending on the quality of the plastic used by the manufacturer. In cheaper models Indesit or Beko the plastic may be thinner, which makes the sounds more sonorous. Expensive brands like Liebherr or Bosch often use composite materials that dampen noise better, but it is impossible to completely get rid of physics.
Operation of the defrost system and defrost cycle
The key feature of the No Frost technology is the automatic removal of moisture that settles on the evaporator in the form frost. For this purpose, the design provides a special defrost cycle, which is triggered by a timer at certain intervals of compressor operation. It is at this moment that users most often hear a characteristic crackling or even hissing.
When the timer gives the command to defrost, the heating element (heating element) located next to the evaporator is turned on. The ice that has accumulated during the cooling cycle begins to actively melt. A sharp change in temperature from sub-zero to positive causes intense expansion of the metal parts of the evaporator. The sound can be quite loud, reminiscent of the crackling of wood in a fireplace or the bursting of bubbles.
In addition, water is involved in the process. Moisture dripping from the evaporator falls onto the hot heating element or into the drain pan, where it can briefly boil or actively evaporate. This creates additional sounds that may be mistaken for a malfunction. It is important to understand that in a working refrigerator these processes occur regularly, usually several times a day.
If the crackling noise occurs strictly periodically, for example, every 8-12 hours, and lasts about 20-30 minutes, then this is normal operation of the system. At this time, the compressor is usually turned off, and the fan may not work so as not to blow warm air through the chamber. After the defrost cycle is completed, the refrigerator switches back to cooling mode and the sounds stop.
Why is the crackling noise louder at night?
At night, the level of background noise in the apartment is minimal, so the sounds of appliances seem louder. In addition, temperature changes at night can be more dramatic due to the lack of solar heating, which enhances the effect of expansion of materials.
Problems with the No Frost system fan
Circulation of cold air in the refrigerator chambers is provided by a fan. If you hear not just a crackling sound, but a sound that resembles friction, grinding, or uneven humming that turns into a crackling sound, the problem may lie in this unit. The fan is located behind the back wall of the freezer or refrigerator compartment and is accessible only after partial disassembly.
One of the common causes of noise is ice freezing on the fan blades or on its rotation axis. Even in the No Frost system, local ice formation is possible if the tightness of the door seals is broken or the drainage is clogged. The ice crust interferes with free rotation, and the blades begin to touch the walls of the casing, producing a characteristic crackling sound.
Another reason is wear of the bearings or bushings of the fan motor. Over time, the lubricant dries out and the axle begins to play. This leads to beating and vibration, which are transmitted to the refrigerator body. In such cases, the cracking sound may intensify when you open the door, since in many models the fan turns off when you open the door, and the startup occurs with a jerk.
- ❄️ Ice buildup: Check whether ice has formed on the back wall of the chamber, which can block the fan.
- 🌀 Bearing wear: If the fan is humming and crackling constantly, most likely, it requires replacement or lubrication.
- 🚪 Operating mode: Pay attention to whether the sound changes when opening and closing the refrigerator door.
Malfunctions of the defrost heating element and timer
If the crackling noise when operating the No Frost refrigerator becomes too loud, similar to electric shocks or strong hissing, you should pay attention to the serviceability of the defrosting heating element. In normal condition, the heating element should operate silently, heating the evaporator. However, if the contacts fail or are broken, extraneous sounds may occur.
A dangerous symptom is the situation when the heating element continues to heat up even after the defrost cycle has completed. This can lead to overheating of the plastic parts of the air ducts, their deformation and the appearance of a burning smell combined with the crackling sound of melting plastic. There may also be problems with defrost timer or the electronic control module, which incorrectly sends signals to turn on the heater.
In some cases, the cracking noise is caused by the very process of burning out the nichrome coil of the heating element. If there is a defect in the heating element, a micro-short or sparking may occur when voltage is applied, accompanied by clicking sounds. This requires immediate diagnosis as it can lead to a short circuit.
Diagnosis of these components requires the use of a multimeter to check the resistance. The normal resistance of a heating element is usually several hundred ohms. If the device shows a break or, conversely, too low resistance, the element must be replaced. You should also check the integrity of the wiring going to the heater.
⚠️ Attention: Checking the electrical components of the refrigerator should only be carried out with the device completely disconnected from the network. Do not touch live parts under voltage.
Plastic deformation and design features
Build quality and materials used play a huge role in acoustic comfort. In budget refrigerator models, manufacturers can use cheaper types of plastic for internal panels and containers. Such plastic has a high coefficient of thermal expansion and is less resistant to cyclic loads.
Over time, the plastic “gets tired”, microcracks appear in it, which can make sounds when the temperature changes. Plastic guides for shelves, vegetable drawers and decorative inserts on doors especially often crack. If you notice that the sound does not come from the depths of the unit, but from the front, try gently pressing on the plastic elements.
Structural gaps can also cause noise. If the inner panel does not fit tightly against the evaporator body, it will resonate when the compressor or fan operates. The vibration is transferred to the plastic, and it begins to rattle or crackle. This often happens after transportation if the transportation bolts or fixing elements were removed carelessly.
To eliminate such noise, it is often enough to correct the tightly fitting elements or place a soft gasket (for example, a piece of foam rubber or rubber) at the point of contact of the rubbing parts. It is important not to use flammable materials and not to block the openings for air circulation.
☑️ Diagnosis of the sound source
Refrigerator noise diagnostic table
To simplify the task of determining the cause of the crackling sound, use the following table. It will help to compare the nature of the sound with a probable malfunction and the necessary actions.
| Sound type | Periodicity | Probable cause | Necessary actions |
|---|---|---|---|
| Rare clicks, crackling | When turning on/off | Thermal expansion of materials | Normal, no intervention required |
| Loud crackling, hissing | Every 8-12 hours | Operation of the defrost system (heating element) | Normal, checking drainage in case of puddles |
| Grinding, uneven hum | Constantly or cyclically | Fan malfunction | Disassembling, removing ice, replacing the fan |
| Severe crackling, burning smell | Constantly or chaotically | Faulty heating element or wiring | Turn off immediately, call a technician |
| Plastic rattling | When the compressor vibrates | Poor fit of the panels | Tighten the fasteners, seal the gaps |
By analyzing the data from the table, you can significantly narrow down the search for the problem. However, remember that visual inspection of internal components often provides more information than just listening.
Elimination methods and prevention
If you are convinced that the crackling noise is not normal, you need to begin eliminating the cause. The first step should always be complete defrosting the refrigerator. Even if ice is not visually visible, it may be hidden behind plastic panels. Unplug the device, open the doors and leave for at least 24 hours.
After defrosting, carefully inspect the fan and evaporator. Remove all ice and check that the impeller rotates freely. If the problem was freezing, after this procedure the noise should disappear. For prevention, regularly check the tightness of the door seals - warm air getting inside causes excessive frost formation.
In case of mechanical wear of the fan or malfunction of the heating element, parts will need to be replaced. Independent repair of the electrical part is possible only if you have the skills to work with a multimeter and understand the circuit diagram of the device. If you are not confident in your abilities, it is better to contact a service center, especially if the refrigerator is under warranty.
It is also worth checking the installation level of the refrigerator. Use a spirit level to ensure the unit is level. Adjusting the height of the legs will help eliminate misalignment, which can cause stress in the tubes and cabinet, increasing expansion sounds.
⚠️ Note: Specifications and layouts of refrigerators may vary between brands. Before disassembling, read the instructions for your specific model, since the location of the fasteners and the type of parts may be unique.
When you need to call a specialist
Despite the possibility of self-diagnosis, there are situations when you cannot do without a specialist. If, after defrosting and checking the fan, the crackling does not stop, and the nature of the sound indicates an electrical nature (sparking, smell), further experiments are dangerous.
Also, the help of a technician is needed if the crackling is accompanied by a change in the operating mode of the refrigerator: it stops freezing, works without interruption, or, conversely, turns off too often. This may indicate problems with the thermostat, defrost sensors or compressor, which require professional diagnostic equipment.
Do not ignore repeated relay clicks if they become too frequent. This may be a sign that the compressor is “clocking” due to problems with the start relay or low voltage in the network. Long-term operation in this mode will quickly damage the motor.
Is it possible to use a refrigerator with a crackling sound?
If the crackling sound is caused by thermal expansion or normal defrosting, yes. If the sound is mechanical (fan grinding) or electrical, it is better to stop using it until the reasons are determined, so as not to aggravate the breakdown.
Is it normal for a refrigerator to crack immediately after purchase?
Yes, this is absolutely normal. New materials (plastic, metal) have not yet gone through expansion-compression cycles, so in the first weeks of operation the sounds may be more pronounced. Over time, they will become quieter or disappear.
Can a compressor make noise?
The compressor itself usually hums. The cracking noise may come from a start relay located near it, especially if it is faulty. Also, sounds can be transmitted through tubes from a vibrating motor to the body.
Does the amount of products affect the noise level?
Indirectly - yes. A full refrigerator maintains its temperature better, the compressor turns on less often, and, accordingly, expansion cycles occur less frequently. An empty refrigerator heats up faster, turns on more often and reacts more actively to temperature changes.
What to do if a cracking sound appears after defrosting?
Make sure you completely dry the refrigerator before turning it on. Residual moisture may have frozen in unintended places and is now interfering with the operation of the fan. Let the device operate for several hours - the ice may melt on its own during operation.
Is cracking noise dangerous for food?
The sound itself is not dangerous. What's dangerous is what's behind the sound. If the cracking sound indicates a problem with the cooling system, the temperature in the chamber may rise, causing food spoilage. Control the temperature inside the chamber.