How to tell if refrigerator compressor is bad

The compressor is the most important part of the refrigerator. It serves for a long time, however, it can still fail. Let’s figure out how to determine that it is faulty.

The breakdown of the unit is not necessarily accompanied by an absolute absence of cold. The refrigerator may continue to work, the cold will flow into the refrigerator and freezer, but this does not mean that the device is working properly and works as expected. As a rule, the compressor of the refrigerator fails as a result of a prolonged overload or emergency situations.

The functioning of the refrigerator is based on the circulation of the refrigerant in the system, for which the compressor and its drive are responsible. Often this unit is called a motor-compressor due to the similarity of the functional load of the electric motor and the compressor, which creates an excess pressure of the circulating freon. Violations in the operation of the unit are primarily indicated by extraneous noise, overheating, insufficient cooling, or turning it off and on too often.

Compressor symptoms

First of all, the breakdown is evidenced by a constant violation of the temperature regime. The operation of the refrigerator is a cycle change, switching on and off is directly related to the temperature level in the chambers of the device. Sensors and relays send a pulse to turn the compressor on and off, however, if the unit is not working at full capacity, the temperature will not be cold enough to turn off the relay.

The causes of the breakdown must be sought in stages: exclude possible options one by one. If the refrigerator compressor works all the time and does not stop, then the search for the cause is simplified, however, in this case, it may not be only in the unit itself. Excessive cooling may be a sign of a malfunction in the temperature detection and control system of the device.

The following signs indicate the failure of the compressor itself:

  • extraneous sounds during operation;
  • overheating;
  • frequent switching on and off of the start relay;
  • oily liquid under the refrigerator;
  • a loud hum of the engine with no signs of compressor operation.

Compressor symptoms

All these moments signal a problem in the motor-compressor assembly. But since this block is two units, it is necessary to distinguish between their malfunctions. This is the immediate task of the specialist. Do not repair the refrigerator compressor on your own. The release of circulating refrigerant can harm you.

Extraneous sounds during operation

Loud noise, knocking, grinding and rattling should alert you. The refrigerator compressor usually makes the following sounds: in good condition, a quiet hum is heard, followed by silence during shutdown. There shouldn’t be any loud noise. In addition, knocking or screeching when turning off also indicates problems with the compressor. Inside it has an electric motor, which rests on springs. Extraneous noises also indicate problems with the engine. But the rattle and knock may indicate a breakdown of the fastener. A defective compressor must be replaced, although it is often better to replace the entire refrigerator.


In normal operating condition, the compressor should be slightly hot, around 45-60 degrees Celsius. Severe overheating indicates a malfunction. There may be several reasons for this. Most often, overheating occurs due to insufficient refrigerant. There may be a leak somewhere, or low refrigerant charge. For this reason, the compressor is overloaded and overheated. If the lack of refrigerant is not eliminated, it can accelerate the wear of the unit. Also, if the compressor is too old, it will overheat simply due to wear.

Refrigerator Compressor Overheat

As a rule, a specialist invited to inspect the refrigerator checks the refrigerant level. If there is enough coolant, but the compressor is still overheating, it most likely needs to be replaced. The unit usually costs a lot. Replacing it is advisable in case of high cost of the refrigerator, and also if it is a high-quality or industrial refrigerator. In the case of an ordinary household one, it is easier to buy a new one.

Frequent switching on and off of the trigger relay

When using the refrigerator, users sometimes notice that the device turns on and off too often. The compressor must periodically turn off when the refrigerator reaches a certain temperature. But we are talking about too frequent switching on and off without reaching the required temperature. The reason for this may be the start relay. To figure out if this is the case, first of all, unplug the refrigerator from the mains. Then remove the relay and shake, listening carefully. If you hear a rattling, then the reason is in the relay. If not, then it’s the compressor.

If you found that the relay is working properly, then the refrigerator may not be working properly due to some kind of compressor overload that causes frequent switching on and off. The compressor performs the function of compressing the refrigerant circulating through the refrigerator. So overloading this unit can cause a serious problem, it must be fixed as soon as possible.

The situation with a compressor malfunction is quite serious, so unplug the device in advance and invite a wizard to solve the problem. Minor breakdowns of the refrigerator can be fixed on your own, but not in the case of a compressor. The circulating refrigerant and the possibility of overloading the unit are fraught with serious consequences, so it is better to contact specialists. Repair of the refrigerator compressor in this case is impossible, so you will have to replace it.

Frequent switching on and off of the trigger relay

The main reasons for the failure of the unit

  • voltage drops;
  • contamination of the condenser coils;
  • leakage or contamination of the refrigerant;
  • wear due to long-term operation;
  • relay failure, etc.

Sometimes the compressor also fails due to valve sticking, winding breakage, damage to the electronic board, and a decrease in motor performance.

Voltage drops

This is extremely dangerous for household appliances. During power surges, the refrigerator is subjected to a sharp surge of electric current, and, as a result, it overheats greatly. There are frequent cases of such power surges in a thunderstorm, due to lightning strikes. In other words, such voltage drops “fry” the mechanisms of the refrigerator, in particular, the compressor.

Condenser coils dirty

Fouled condenser coils

Dirty condenser coils can cause refrigerator compressor failure. If they are dirty, it makes it difficult to cool the device. As a result, the compressor works more than it should, the refrigerator overheats and wears out. The condenser may even jam, the compressor will not be able to work, the refrigerator will not cool.

Refrigerant leak or contamination

The purpose of the compressor is to compress the circulating refrigerant. The unit creates such pressure that the refrigerant turns into a liquid. The cooling process requires a certain amount of refrigerant. Leakage leads to a decrease in the level of cooling. Such problems lead to compressor failure. There may be too little or too much refrigerant, or it may be contaminated for some reason.

Refrigerant leak or contamination

Wear due to long-term use

All components are designed for a certain service life. A good quality compressor will usually run for many years without problems. If the refrigerator is too old, then the compressor is probably defective. And the reason for this is primarily natural wear due to a long service life. The cost of the unit is usually high. Often it is more profitable to simply buy another refrigerator. But if you have a new, high-end refrigerator, it might be better to buy a compressor.

Relay failure

The relay is the mechanism that starts the compressor. If the relay is faulty, the unit will not operate. But if it’s a relay, then it’s not so scary: it’s enough just to change it. It is not difficult to identify a relay malfunction, just remove it, shake it and listen. If you hear a rattling sound, then the relay needs to be replaced. If you decide to handle this task yourself, first unplug the refrigerator from the mains. Then remove the rear access panel of the refrigerator. For more convenience when replacing the relay, refer to the user manual.