Sooner or later, every owner of household appliances faces the problem of noise, vibration or sudden shutdown. Often the cause of a malfunction is the compressor, namely wear of rubbing parts due to lack of lubrication. The question of how to add oil to a refrigerator compressor faces those who decide to extend the life of the unit on their own without contacting a service center.
The process of replacing or adding lubricating fluid requires accuracy, the presence of a special tool and, most importantly, an understanding of the operating principles. sealed circuit. Incorrect actions can lead to final failure of the unit or even depressurization of the system. In this article we will analyze in detail the technology of work, the selection of suitable materials and typical mistakes.
It is important to understand that modern refrigerators are equipped with non-separable compressors, where oil circulates in a closed cycle along with the refrigerant. If the lubricant level has dropped, it means that there has been a leak somewhere or oil has accumulated in the heat exchangers. Before starting repairs, it is necessary to diagnose the condition of the engine.
Diagnostics of the oil level and signs of its lack
The first sign that the lubrication system has failed is a change the nature of the refrigerator's operation. The engine starts to run louder, and a metallic knocking or humming noise appears that was not previously observed. In some cases, the compressor may overheat and turn off by the thermal relay, not having time to reach the desired temperature in the chambers.
If you notice oily spots on the floor under the back wall of the refrigerator, this is a sure sign of depressurization. Oil does not disappear by itself and does not burn in a working unit. Its presence on the outside means that the integrity of the pipes or seals has been compromised. Visual inspection of the compressor often helps to localize the leak.
⚠️ Attention: If the compressor runs “dry” for more than 15-20 minutes, there is a risk of the piston group jamming or rotor is more than 90%. Do not ignore the first signs of noise.
To accurately diagnose the oil level inside the system, a pressure gauge station and experience are required. However, at home, you can focus on indirect signs: lack of cold when the engine is running, a hot compressor housing and the characteristic sound of “gurgling” or liquid pouring in the tubes.
Selecting the appropriate type of oil for the compressor
A critically important step is selecting the correct lubricant. Using the wrong composition may result in a chemical reaction with the refrigerant, acid formation and complete destruction of the insulation of the motor windings. Modern systems use synthetic oils, which are divided into several main types depending on the type of freon.
The most common are polyester oils (POE), which are used with ozone-friendly refrigerants R134a, R404A, R600a. They are highly hygroscopic, that is, they actively absorb moisture from the air, so they need to be stored in a tightly closed container. Mineral oils (MO) are found in older models using R12 freon, but their use today is limited.
When choosing, pay attention to the viscosity. It is designated by a numerical code (ISO VG). For household refrigerators, oils with a viscosity of 15, 22 or 32 are most often used. Replacing one type of viscosity with another is allowed only in exceptional cases and with a full understanding of the consequences for the lubrication system.
Necessary tools and workplace preparation
To perform oil change work, you will need not only the liquid itself, but also specialized tools. A standard home repair kit will not work here, since the system is under pressure and requires vacuuming. Before starting work, make sure that the refrigerator is unplugged from the power supply for at least 2 hours.
You will need the following tools and materials:
- 🔧 Pressure gauge station with a set of hoses (blue and red).
- 🔌 Vacuum pump to remove moisture and air from the circuit.
- 🛢️ A syringe or measuring container for precise dosing of oil.
- 🔥 Gas torch or torch with solder (for soldering copper tubes).
- 🧼 Solvent or special liquid for flushing the system.
The workplace must be well ventilated, as refrigerant and oil vapors can be harmful to health. Prepare in advance a container for draining old oil and rags for cleaning. Safety —priority number one when working with refrigeration equipment.
☑️ Preparing to change the oil
Technology for changing oil through the process pipe
There are two main ways to change the oil: through the suction pipe (without opening the system) and a complete replacement with flushing. The first method is suitable if you just need to top up the level or change the oil in a working compressor during routine maintenance. Let's consider the procedure for this method.
First you need to gain access to the process pipe, which is usually sealed. Carefully file or cut off the end of the tube to install the gauge station fitting. Connect the blue hose (low pressure) to the fitting and the yellow hose to the vacuum pump. Turn on the pump and create a vacuum in the system to remove any remaining old oil and air.
The vacuum process should last at least 15-20 minutes until the reading reaches -1 bar (or 750 mm Hg).After creating a vacuum, close the valve on the pump, disconnect the hose from the pump and lower its end into a container with new oil. By opening the valve, you allow atmospheric pressure to force oil into the compressor. Control the volume using the scale on the syringe or measuring container.
How much oil should be poured?
The exact volume of oil is indicated in the technical documentation of the refrigerator model. Typically for household compressors this value ranges from 150 to 300 grams. Overfilling the oil is just as dangerous as underfilling: it causes hydraulic shock and destruction of the valves.
Flushing the system and removing old oil
If the compressor burns out or contamination occurs in the system, simply topping up is not enough. A complete flush of the circuit is required. Old oil mixed with insulation decomposition products and acids must be completely removed, otherwise a new portion of lubricant will instantly become contaminated.
Rinsing is carried out using nitrogen under pressure or special flushing liquids (solvents), which are then removed by vacuum. The procedure is complex and requires disassembling the circuit: unsoldering the condenser, filter drier and evaporator. Filter drier In this case, it is always replaced with a new one, since the old one is already saturated with moisture and will not be able to work effectively.
The table below shows the main stages of washing and changing the oil during a major overhaul:
| Work stage | Description of action | Required tools |
|---|---|---|
| 1. Dismantling | Soldering the old compressor and filter | Burner, pipe cutter |
| 2. Flushing | Purge the circuit with nitrogen or solvent | Nitrogen cylinder, hoses |
| 3. Installation | Installation of a new compressor and filter | Solder, flux |
| 4. Evacuation | Removing moisture and air from the system | Vacuum pump |
| 5. Refilling | Filling oil and refrigerant by weight | Electronic scales, freon |
⚠️ Attention: After opening the system and soldering, be sure to replace the filter drier. The old absorbent will not be able to remove moisture, which will lead to the formation of an ice plug and corrosion from the inside.
Refrigerant charging and final check
After the oil has been filled, it is necessary to charge the system with refrigerant. The amount of freon must strictly correspond to the norm indicated on the refrigerator nameplate (usually in grams). Electronic scales are used for accurate filling. An excess of refrigerant will lead to increased pressure and load on the compressor, and a deficiency will lead to insufficient cooling.
After refilling, turn on the refrigerator and let it run in test mode for at least 2-3 hours. Monitor the temperature of the compressor housing and the nature of its operation. Normal temperature The housing should not exceed 60-70 degrees Celsius (the hand is hot, but tolerable).
Check for leaks at the solder joints using a soap solution or a leak detector. Bubbles will indicate seam defects. If all the parameters are normal, you can install the protective cover and slide the refrigerator into place.
Is it possible to use car engine oil for a refrigerator?
No, absolutely not. Automotive oils have a different chemical base and are not compatible with refrigerants and rubber seals of the refrigeration system. Their use is guaranteed to cause the compressor to fail in a short time.
How often do you need to change the oil in the compressor?
In a working hermetic compressor, the oil is designed for its entire service life (10-15 years) and does not require scheduled replacement. Replacement is made only when repairing, replacing the compressor or detecting signs of contamination/leakage.
What to do if after changing the oil the refrigerator does not freeze?
Possible reasons: moisture entering the system (capillary clogged), incorrect amount of refrigerant, air lock or malfunction of the newly installed compressor. Repeated diagnostics with a pressure gauge station is required.