An extraneous hum, an increasing hum or periodic crackling noise coming from the refrigeration chamber often indicates problems with the forced air circulation system. In modern models No Frost it is the electric fan that is responsible for the uniform distribution of cold, and its incorrect operation immediately affects comfort. Many equipment owners, upon hearing an unpleasant sound, begin to panic and call a technician, although in most cases the problem is solved on their own in one evening.
The key point in restoring the silent operation of the unit is the correct choice of lubricant. An error in the selection of the composition can lead to the fact that after a couple of months sliding bearing it completely jams, and the assembly itself will have to be replaced entirely. It is important to understand that specific conditions reign inside the refrigerator: low temperature, high humidity and constant contact with food, which imposes strict restrictions on the chemicals used.
In this article we will analyze in detail which compositions are really suitable for servicing the motor, and which ones it is better to refrain from so as not to harm the equipment. You will learn about the physical and chemical properties of various oils and receive step-by-step instructions for dismantling and servicing the unit without calling service.
Why is the fan humming in the refrigerator
The main reason for the noise is the drying out of the factory grease in sliding bearings. During long-term operation, the oil loses its viscosity characteristics, evaporates or thickens in the cold. As a result, the shaft begins to rotate with increased friction, which generates a characteristic hum, which turns into a squeal when the load on the compressor increases.
Another reason may be an imbalance of the blades or the entry of foreign objects, for example, pieces of ice or crumbs, into the working area of the impeller. However, if there are no mechanical obstacles, and the sound resembles the friction of metal on metal, then we are talking about the need to service engine bushings.
⚠️ Attention: If, when turning the blades by hand, you feel a clear play in the shaft or it moves very tightly even after lubrication, it means that the bushing itself has worn out. In this case, the lubricant will only have a temporary effect, and the unit will need to be replaced.
Sometimes the noise occurs due to frozen ice touching the blades. This happens when the defrost system malfunctions, when the drainage hole becomes clogged and the water does not flow into the pan, but freezes around the evaporator. Before you go with the lubricant, make sure that the fan housing is clean and not overgrown with a fur coat.
Strictly prohibited lubricants
The most common mistake is the use of universal penetrating lubricants, such as WD-40. Many people mistakenly believe that if a product removes squeaks in door hinges, it will also be suitable for the refrigerator. This misconception could cost you a working fan.
The fact is that WD-40 is not a lubricant, but a solvent with a small amount of oil added. Its task is to displace water and wedge rust. Once inside the bearing, it will first wash away the remaining factory lubricant and then quickly evaporate. After this, the friction will increase many times over, and the shaft will jam within several weeks.
- 🚫 WD-40 and analogues - wash off the protective layer and dry, leaving dry friction.
- 🚫 Vegetable oil - over time polymerizes, turning into a sticky resin that tightly glues the mechanism.
- 🚫 Solidol and Litol-24 —at low temperatures (below -20°C) they become very thick, preventing the fan from gaining operating speed.
- 🚫 Machine motor oil —may have too strong a smell, which will be absorbed into the food, and is not designed for use in the food area.
Why can’t you use graphite lubricant?
Graphite lubricants are conductive. If they come into contact with motor windings or contacts, they may cause a short circuit. In addition, graphite is an abrasive that will accelerate the wear of soft sliding bushings used in most household fans.
Suitable materials for maintenance
To lubricate components operating inside the refrigeration chamber, it is necessary to use synthetic oils that remain fluid at subzero temperatures. The ideal option is silicone lubricants special synthetic oils for sewing machines and household appliances.
Silicone compounds are inert, odorless, do not destroy plastic and rubber, and do not thicken in the cold. They create a stable film that ensures long and quiet operation of the mechanism. It is also acceptable to use synthetic oils based on polyalphaolefins (PAO), which are often used in refrigerator compressors.
The table below compares the main types of lubricants according to their suitability for this task:
| Lubricant type | Temperature mode | Drying resistance | Suitability |
|---|---|---|---|
| Silicone oil | from -60°C to +200°C | High | Excellent |
| Synthetics for sewing machines | from -30°C to +150°C | Average | Good |
| WD-40 | from -50°C to +100°C | Low (evaporates) | Prohibited |
| Mineral oil | from -10°C to +90°C | Medium | Not recommended |
Preparation and safety precautions
Before you begin disassembling, you must completely turn off the power to the refrigerator. Unplug the plug from the outlet. This is a basic rule of electrical safety, ignoring which can lead to electric shock, since the humidity inside the case is high.
You will need a minimum set of tools: a Phillips screwdriver, a flat-head screwdriver (for carefully prying up the latches), cotton swabs, a lint-free cloth and a syringe with a thin needle for pinpoint application of lubricant. It is also worth preparing a container for melt water if you need to defrost the unit.
- 🔌 Turn off the power - unplug the cord.
- ❄️ Defreeze camera - leave the refrigerator open for at least 10-12 hours so that all the ice melts.
- 🧤 Protect the floor —lay down rags, as water may leak out of the drainage.
⚠️ Attention: Do not try to remove frozen ice with a knife or other sharp objects. Damage to the evaporator will lead to freon leakage and expensive repairs, which are not economically feasible.
☑️ Tools for work
Removing and cleaning the fan
In refrigerator systems No Frost The fan is usually located at the top of the freezer or behind the back panel. To access it, you need to remove the plastic cover, which is often secured with screws and plastic latches. Proceed carefully, plastic becomes brittle in the cold.
After removing the panel, you will see the fan itself. It is often secured in rubber dampers or screwed to the evaporator body. Disconnect the electrical connector and wires. Pay attention to the position of the connector so as not to reverse the polarity during assembly, although in modern models the connectors have keys to prevent erroneous connection.
Remove the motor from the seat. Thoroughly clean the body, blades and axle of dirt, dust and residues of old thickened grease. For cleaning, you can use alcohol or special contact cleaners, but do not allow them to get inside the motor windings.
Lubricating process and assembly
The most critical stage is applying a new lubricant. There is usually a sticker on the motor housing that hides the hole for the shaft. Carefully remove it or find the technological hole near the shaft exit.
Using a syringe with a needle, inject 2-3 drops of silicone oil directly into the gap between the shaft and the bushing. Do not pour too much oil; excess may splash during operation and stain the food. After applying the lubricant, rotate the shaft several times with your fingers so that the oil is distributed over the entire friction surface.
Put the motor in place, secure it and connect the connector. Before screwing on the lid, turn on the refrigerator and check the operation of the fan. If the hum has disappeared and the impeller rotates easily and silently, you can reassemble the structure in the reverse order.
What to do if the fan continues to make noise?
If the lubrication did not help, perhaps the reason is wear of the bearings (play has appeared) or a malfunction of the electric motor itself (interturn short circuit of the windings). In this case, only complete replacement of the unit with a new one will help. Also check if the power wires are broken.
Is it possible to lubricate the fan without removing it?
Theoretically, you can try to drip oil through the gap in the housing without removing the motor, but the effectiveness of such a procedure is extremely low. You will not be able to properly clean the shaft from old dirt, and the lubricant will lie on top of it. Complete disassembly is recommended for a guaranteed result.
How often should the procedure be repeated?
High-quality silicone grease lasts a long time. Typically, re-service is required after 3-5 years of operation. If the noise appears again after a month, it means that the wrong lubricant was used or the mechanism is critically worn.
Does lubricant affect the warranty?
Independent opening of sealed components and violation of the integrity of the factory stickers on the engine may become grounds for refusal of warranty service. If the refrigerator is under warranty, it is better to contact an authorized service.
What is the melting point of the lubricant?
Silicone oils retain their properties over a wide range of temperatures, usually from -60°C to +200°C. In refrigerator conditions, where the temperature rarely drops below -24°C, the risk of high-quality lubricant freezing is practically eliminated.