A sudden breakdown of the refrigerator often becomes an unpleasant surprise, especially when there are perishable foods left inside. One of the common causes of failure is engine jamming, which in many cases is associated with degradation of the lubricant. Understanding how to change the oil in a refrigerator compressorcan save expensive equipment from disposal and extend its life for several years.
Many craftsmen immediately suggest replacing the entire unit, arguing that it is impossible to repair, but in some cases a simple change of lubricant works wonders. If your refrigerator stops turning on, hums but won't start, or makes strange sounds when trying to start, the problem may lie in thickened or burnt-out oil. It is important to understand that this procedure requires accuracy, the availability of tools and basic skills in working with equipment.
Before taking active steps, you need to make sure that the diagnosis is correct. Sometimes the symptoms are similar to a faulty start relay or thermostat, so diagnosis is the first and most important step. In this article, we will analyze in detail the process of selecting the right type of lubricant, the technology for replacing it without the use of welding, and precautions that will protect you from mistakes.
Diagnostics of compressor malfunctions
The first sign that oil in the compressor has become unusable is a characteristic sound at startup. The motor tries to start, a hum or click is heard, but after a few seconds it goes silent and the thermal protection is triggered. This condition is often called "wedge" when the piston group cannot turn due to lack of lubrication or the presence of thick deposits. However, do not rush to disassemble the unit until you check the electrical part.
It is necessary to ring the motor windings and check the starting relay. If the electrical circuit is intact and the relay is working properly, but the motor shaft does not rotate manually (with the power off), then the likelihood of problems with the lubricant is high. In older models of refrigerators, such as Atlant or Biryusa, this often happens due to long-term operation without maintenance.
⚠️ Attention: Before any diagnostics, be sure to Unplug the refrigerator from the power supply! Working with live electrical components is deadly.
It is also worth paying attention to the color of the oil, if it is possible to see it through the service pipe. Normal fluid should be clear or slightly yellowish. If you see a black, viscous mass with a burning smell, then oil change it is necessary immediately. Ignoring this fact will lead to complete destruction of the rubbing parts of the compressor.
Sometimes the problem lies not in the oil itself, but in its insufficient quantity. Leaks occur through leaking connections or seals, if they are structurally provided for. In such cases, simple topping up may not help if irreversible wear processes have already begun in the system. Therefore, a visual inspection and “listening” to the operation of the engine provide a primary understanding of the scale of the disaster.
Selecting the appropriate type of oil
A critically important point is the correct selection of lubricant. Refrigerator compressors operate in a closed circuit where oil circulates along with refrigerant. This means that the liquid must have specific properties: low pour point, chemical inertness and a certain viscosity. Using the wrong oil will lead to rapid failure of even a new compressor.
There are two main types of oils that are used in household refrigeration equipment. The first type is mineral oils, which were used in older models running on freon R-12. The second type is synthetic oils, most often based on polyesters (POE), which are necessary for modern refrigerants, such as R-134a i R-600a. Mixing these types is strictly prohibited as they may react and form acid.
When choosing, pay attention to the viscosity. For domestic refrigerators, oils with a viscosity of 16 to 22 CST at 40°C are typically used. Popular brands that have proven themselves in the market include Emkarate, Bitzer and Mobil. Buying oil "from hand" or on tap without a label is a lottery that can cost you a new compressor.
Below is a table of correspondence between refrigerants and oil types that will help you navigate:
| Refrigerant type | Recommended oil type | Features | Examples of brands |
|---|---|---|---|
| R-12 (Freon-12) | Mineral | High hygroscopicity, afraid of moisture | Mobil EAL, Bitzer BVC |
| R-134a | Synthetic (POE) | Aggressive to rubber seals | Emkarate RL 32H, Bitzer BSE |
| R-600a (Isobutane) | Synthetic (POE/PAG) | Explosive gas, requires caution | Emkarate RL 22H, Danfoss 160P |
| R-404A / R-507 | Synthetic (POE) | Used in industrial and large cameras | Emkarate RL 68H, Suniso 4GS |
It is worth noting that modern synthetic oils are highly hygroscopic, that is, they actively absorb moisture from the air. Therefore, it is impossible to store an open canister for a long time, and the replacement procedure itself must be carried out as quickly as possible, minimizing contact of the oil with the atmosphere. Moisture in the system guarantees the formation of ice plugs and acids that corrode the metal from the inside.
Necessary tools and preparation
To carry out a quality replacement, you will need a certain set of tools. Do not try to change the oil "on the knee" without preparation, as this can lead to system contamination or injury. The main tool will be a pipe cutter, which allows you to make an even cut of a copper pipe without the formation of chips.
You will also need: pliers, a blowtorch or torch (if you plan to solder), a vacuum pump (preferably, but you can do with other methods), a container for draining waste and a funnel or syringe for pouring new oil. Do not forget to prepare rags and gloves, as oil is difficult to wash off, and old waste can be toxic.
☑️ Preparing to change the oil
Work should be carried out in a well-ventilated area. Although the amount of refrigerant in a household refrigerator is small, it is not advisable to get it in your eyes or on your skin. In addition, when copper pipes are heated, oxide can be released, so the presence of ventilation or working outside is a prerequisite for safety.
Before starting manipulations, the refrigerator must be rolled out into a free space to provide access to the back wall from all sides. The compressor is usually located in the lower niche, sometimes covered with a casing. Remove the casing, if any, and remove dust from the unit so that it does not get inside when opening the circuit.
Technology for changing oil without soldering tubes
There is a method that allows you to change the oil without the use of welding and complex equipment, which is especially important for home conditions. The essence of the method is to use standard technological holes or minimal intervention in the system. First you need to find the suction tube of the compressor (it is usually thicker than the others) and carefully file it or cut it off with a pipe cutter.
After this, turn the compressor 45 degrees in the direction opposite to the outlet of the tubes, and allow the oil to drain into the prepared container. The process may take from 30 minutes to an hour. To speed up the process and remove any remaining old oil from the internal cavities, you can gently rock the unit. However shake the compressor violently not recommended so as not to damage the internal engine suspension.
To flush the system, you can use a special flushing solution or a small amount of new oil, which is driven through the system and drained. This helps remove decay products and acid residues. After draining the flushing liquid, it is necessary to let the compressor stand in an inverted position for some more time so that the residue drains as completely as possible.
Filling in new oil is done through the same suction tube. It is most convenient to use a large medical syringe with a long needle or a funnel with a thin spout. The volume of oil poured is strictly regulated for each compressor model (usually from 150 to 300 grams). Overfilling oil is just as dangerous as underfilling: excess liquid can cause water hammer or worsen heat transfer in the condenser.
⚠️ Attention: The exact volume of oil is indicated on the compressor nameplate or in the technical documentation. Do not pour oil by eye; use a measuring container.
After pouring, the hole should be temporarily closed with a gloved finger or a stopper to avoid air being sucked in. The compressor then returns to its operating position. At this stage, it is important not to immediately connect the system to the refrigerator pipes if you are planning evacuation.
Bleeding the system and removing air
The air trapped inside contains moisture and nitrogen, which, in combination with oil and refrigerant, form aggressive compounds. Therefore, removing air is a critical step. The ideal option is to use a vacuum pump that is connected to the service pipe. The pump pumps out air and moisture vapor, creating a vacuum.
If there is no vacuum pump, you can use the “displacement” method. To do this, turn on the compressor for a short time (literally for 10-15 seconds), creating pressure, then shut off the outlet and allow it to cool. As it cools, a vacuum forms inside, which sucks in any remaining air the next time the valve opens. This procedure is repeated 3-4 times. However, this method is less effective and leaves more moisture in the system.
While the compressor is pumping, monitor the housing temperature. It shouldn't overheat. If the motor hums too loudly or gets hot, stop the procedure and let it cool. Operation without normal load and cooling with refrigerant can be harmful to the windings.
Why can’t you run a compressor for a long time without freon?
The compressor is designed for cooling by the flow of circulating freon. Idle operation leads to overheating of the windings and destruction of the insulation, which can cause a short circuit.
After removing air, you must immediately plug the pipe or solder it if you use the soldering method. Tightness is the key to durability. Any microcrack will lead to the fact that after some time moisture will penetrate inside again, and the entire procedure will have to be repeated.
It is important to understand that without complete evacuation, the life of the compressor can be reduced by 30-40%. Therefore, if you plan to use the refrigerator for a long time, it is better to get an inexpensive vacuum pump or contact a service for this stage.
Startup and performance check
After the oil has been replaced and the air has been removed, you can begin a test run. Connect the compressor to the network through a working start relay. In the first seconds of operation, listen carefully to the sounds: there should be no knocking, grinding or excessive humming. A smooth, monotonous hum indicates normal operation.
Check the heating of the compressor housing. After 10-15 minutes of work, it should become warm, but not scalding. If the housing becomes hot, the oil may be selected incorrectly (too viscous) or there is air left in the system. It is also worth checking the current consumption using a current clamp - it must correspond to the rating indicated on the nameplate.
If the refrigerator starts to freeze, this is the final sign of success. Check the evaporator for uniform cooling. Sometimes after changing the oil, it takes time for the new lubricant to distribute throughout the entire system and reach all rubbing pairs.
During the first day of operation, it is recommended to periodically check the refrigerator for leaks (with a soap solution) and monitor the temperature. If all parameters are normal, the repair can be considered complete. However, remember that such a measure is often temporary if the wear of mechanical parts is already high.
Common mistakes and precautions
One of the most common mistakes is neglecting cleanliness. Getting dust, dirt or moisture into the system is fatal. All tools must be clean and dry. Also, beginners often confuse types of oils, pouring mineral oil into the system under synthetics, which leads to the formation of an emulsion and blockage of the capillary tube.
Another mistake is a violation of proportions. Filling with oil “too much” leads to the compressor starting to “spit” oil into the system, which sharply reduces the cooling efficiency. And a lack of oil leads to instant overheating and jamming. Accuracy in this matter is more important than speed.
⚠️ Attention: If after changing the oil the refrigerator is noisy or does not freeze, an ice or acid plug may have formed in the capillary tube. In this case, the system must be purged with nitrogen, which is only possible under service conditions.
Do not forget about fire safety. Freon R-600aused in many modern models is flammable. A spark from a soldering iron or static electricity may cause a fire. Work carefully, ventilate the room and do not smoke near open pipes.
And finally, you should not revive the compressor if it has obvious mechanical damage or burnt out windings. Changing the oil only helps with lubrication problems, but does not cure a burnt out motor or a damaged shaft. In such cases, it is more rational to replace the entire unit.
FAQ: Frequently asked questions
Is it possible to use automobile engine oil for a refrigerator?
Absolutely not. Automotive oils have a different viscosity, flash point and chemical composition. They are not designed to work in tandem with freon and at low temperatures they will freeze or turn into acid, which will destroy the compressor in a matter of hours.
How often do you need to change the oil in the compressor?
In domestic refrigerators, the oil is designed for its entire service life and does not require scheduled replacement. It needs to be changed only when signs of malfunction appear (jamming, noise) or when repairing the system, when the tightness has been lost and moisture has entered.
How much oil is needed for a regular two-chamber refrigerator?
The volume varies from 150 to 300 grams depending on the compressor model. Always look at the factory sticker (nameplate) affixed to the motor body for the exact number. A deviation of more than 10-15 grams can disrupt the operation of the system.
Why did the refrigerator stop freezing after changing the oil?
Most likely, moisture remained in the system, which froze in the capillary tube, forming an ice plug. It is also possible that the oil was chosen incorrectly or that too much of it was filled, and it clogged the thin channels of the system.
Is changing the oil in an old refrigerator justified?
If the refrigerator is of high quality (for example, old Indesit or Liebherr), then resuscitation makes sense. If it is a budget model with plastic elements and a service life of more than 15 years, it is often cheaper and more reliable to buy a new compressor or the entire refrigerator.