A sudden crackling sound in the rear of the refrigeration unit can unsettle any owner, especially if the equipment was operating silently for years. This sound is often confused with the hum of a motor or the gurgling of refrigerant, but the nature of the crackling sound, as a rule, lies in mechanical vibrations or thermal expansion of materials. To understand whether it is worth calling a technician or whether the problem can be solved yourself, you need to carefully listen to the nature of the sound and determine its frequency.
The situation when refrigerator cracking from the backcan be caused either by absolutely normal processes of the No Frost system or by serious malfunctions of the compressor or fastening elements. In most cases, sharp clicks or periodic crackling indicate heating and cooling of plastic parts, which is the norm, but loud mechanical knocks should not be ignored, as they can signal the failure of important components.
Natural physical processes: thermal expansion
The most common reason why your unit makes sounds is the physical property of materials to change their size under the influence of temperature. During operation evaporator other elements of the circuit heat up and cool down, which leads to microscopic deformations of plastic and metal. These changes in volume are accompanied by a characteristic crackling sound, reminiscent of the sound of a car engine cooling down or the crackling of wood in a fireplace.
This phenomenon is especially often observed in models with a system No Frostwhere defrost cycles occur regularly. The plastic evaporator box, heating up from the defrost element or cooling down during compressor operation, makes sounds that can frighten inexperienced users. If the crackling noise is heard infrequently and is not accompanied by other signs of breakdown, then this is a normal situation that does not require intervention.
The intensity of such sounds depends on the quality of the plastic used manufacturer, and the tightness of the elements to each other. Some brands, such as Liebherr or Bosch, use harder grades of plastic, which may crack louder, but are more durable. Over time, after several heating and cooling cycles, the material adapts, and the noise may become less pronounced.
Malfunctions of the starting relay and compressor electrics
If a crackling noise is heard when the engine starts and resembles an electrical discharge or a loud click, the problem may lie in the starting relay. This small element is responsible for supplying voltage to the motor windings at start-up. When the contacts inside the relay burn or stick, sparking occurs, which is accompanied by a characteristic sound and can cause the refrigerator to stop cooling.
It is important to distinguish the sound of thermal expansion from electrical crackling. The latter is often accompanied by flickering lights in the room or a burning smell. If you hear how The refrigerator is cracking from the back it is in the area where the compressor is located when you try to start, but the motor still does not turn on, most likely the relay has failed and requires replacement. Operating equipment with a faulty starter can lead to the combustion of the compressor itself, which is an expensive repair.
⚠️ Attention: If you suspect an electrical crackling, immediately turn off the power to the device. Continuing to work with a sparking relay may cause a fire or complete breakdown of the motor.
The relay can be diagnosed visually by removing the protective casing at the back of the unit. Often traces of soot or melting are visible on the body of the part. Replacing this element is a simple procedure, but requires compliance with safety precautions and precise selection of the relay model corresponding to the power of your compressor.
Problems with the fan in the No Frost system
In refrigerators with an automatic defrosting system, the fan located in the back wall of the freezer is responsible for circulating cold air. If the fan blades begin to touch frozen ice or a foreign object, a rhythmic crackling or humming occurs, which intensifies when the door is opened (since in many models the fan should stop at this point, but due to inertia or a malfunction of the sensor it can continue to work).
The cause of the noise is often frost on the evaporator, which builds up due to a loose seal on the door or defrost sensor malfunction. The ice crust narrows the space for rotation of the blades, and they begin to literally chop the ice, making unpleasant sounds. In this case, it is necessary to completely defrost the unit within 10-12 hours so that the ice melts and check the free movement of the fan.
☑️ Fan diagnostics
It is also worth checking the fan motor bearing. If it is worn out, rotation becomes uneven and play appears, which causes vibration and knocking. In some cases, lubrication helps, but most often a complete replacement of the unit is required. Pay attention to models Indesit and Atlant, where the fan design may be sensitive to housing misalignment during installation.
Mechanical damage and vibration of the compressor
The compressor is the heart of the refrigerator, and its operation is always accompanied by vibration. If the unit is installed unevenly, or the mounting bolts of the motor itself are loose, vibration is transmitted to the housing and tubes, causing rattling and crackling. This happens especially often if the refrigerator is close to a wall or furniture, and the resonance increases.
Another cause of mechanical noise can be the copper tubes of the circuit. Over time, constant vibration may cause the solder joints to crack, or the tubes themselves may begin to touch each other and the housing. If you hear a metallic ringing or crackling sound, try carefully (with the device turned off) to check the compressor mount and the position of the tubes. Sometimes it is enough to place a rubber damper or slightly bend the tube to eliminate contact.
| Sound type | Probable cause | Nature of manifestation | Urgency of repair |
|---|---|---|---|
| Rare crackling | Thermal expansion | When heating/cooling | Not required |
| Loud click | Start relay | When trying startup | High |
| Rhythmic knocking | Fan (ice) | Continuous or cyclical | Medium |
| Metal ringing | Vibration of tubes | When the motor is running | Low |
How to check the compressor fastening?
To do this, you need to remove the lower rear cover of the refrigerator. Visually inspect the springs or rubber washers on which the motor is suspended. If they fly off or lose elasticity, they need to be replaced or corrected.
Deformation of the housing and external heat exchanger
The back wall of many modern refrigerators is equipped with a condenser grille (coil), which is also subject to thermal expansion. When heated by hot coolant, the metal makes sounds similar to crackling. This is absolutely normal, but if the cracking noise has become too loud, the grille may have become deformed and is touching the body or protective casing.
Sometimes the cause of the noise is the body of the refrigerator itself. If the equipment is standing on an uneven floor, the housing may warp slightly when the compressor operates, causing the panels to rub against each other. Check the horizontal installation using a building level and, if necessary, tighten the adjusting feet. Even a slight misalignment can cause resonance, amplifying any internal sounds.
⚠️ Attention: Do not try to forcefully straighten the condenser tubes on the back wall - they are very thin and easily burst, which will lead to freon leakage.
It is also important to check whether the back wall of the refrigerator is touching the wall of the room or cabinet. The gap should be at least 5-7 cm for free air circulation. If the refrigerator is moved close, the heat is not removed, the motor is overloaded, and the materials heat up more than usual, causing a more intense crackling sound.
Diagnostics and procedure for action when noise occurs
If you find that the refrigerator is cracking from the back, do not panic. First of all, analyze when exactly the sound appears: constantly, only during startup or during defrost cycles. Try to press the back wall or the case itself with your hand - if the sound changes or disappears, it means that the problem is vibration and resonance.
Next you should perform a simple diagnosis:
1. Unplug the refrigerator and let it stand for 10-15 minutes.
2. Turn it on again and listen to the moment it starts.
3. If the crack is electric, call a technician.
4. If the sound is mechanical, check the stability and clearance at the wall.
In cases where the crackling sound is accompanied by an increase in temperature in the chambers, freezing of food or constant humming of the motor without shutdowns, we are talking about a serious malfunction. This may be a loss of circuit tightness, a clogged capillary tube, or wear on the compressor piston group. In such situations, independent repairs can be dangerous and ineffective.
Is it normal if the refrigerator cracks immediately after purchase?
Yes, in the first days of operation, new materials (plastic, metal) undergo an adaptation process. They actively expand and contract, taking on a working shape. Usually, after 3-5 days, the intensity of the sounds decreases.
Can an old refrigerator that was silent before crack?
Yes, over time, the rubber compressor dampers wear out, the lubricant in the fan dries out, and the plastic becomes more fragile. A layer of ice may also accumulate that was not there before due to the aging of the door seal.
Is cracking noise dangerous for the food inside?
The sound itself does not affect the food. The only danger is what lies behind the sound: if, due to a compressor malfunction or freon leak, the temperature in the chamber begins to rise, the food may spoil. Monitor the temperature.
Why does the crackling sound increase at night?
At night, the overall noise level in the room drops, and even the quiet sounds of equipment become noticeable. In addition, voltage drops in the network at night may be higher, which affects the operation of electric motors, causing more pronounced vibration.