1. Lubrication and wear reduction: there is rapid relative sliding between piston and cylinder, and between spindle and bearing bushing. In order to prevent the parts from wearing too fast, it is necessary to establish an oil film between the two sliding surfaces. There is an oil film with sufficient thickness to separate the surfaces of relatively sliding parts, so as to achieve the purpose of reducing wear.

2. Cooling: Engine oil can bring heat back to the oil tank and then radiate it into the air to help the water tank cool the engine.

3. Cleaning: Good engine oil can circulate carbides, sludge and worn metal particles on engine parts back to the oil tank, and wash away the dirt generated on the working surface of the parts through the flow of lubricating oil.

4. Sealing and leak-proof: Engine oil can form a sealing ring between the piston ring and the piston to reduce gas leakage and prevent external pollutants from entering.

5. Rust prevention and corrosion protection: Lubricating oil can be adsorbed on the surface of parts to prevent water, air, acidic substances and harmful gases from contacting with parts.

6. Shock absorption and buffering: When the engine cylinder pressure rises sharply, the load on the piston, piston plate, connecting rod and crankshaft bearing suddenly increases, and this load is lubricated through the bearing, so that the impact load it bears plays a buffering role.

Judging the quality of engine oil:

Look at the packaging

Generally speaking, the packaging appearance of engine oil can be distinguished. The sealing cover of famous brand oil is a disposable cover, and there is sealed tin foil at the gap, which is marked by the manufacturer. If not, it means unprofessional, and it may be fake oil. If there is famous brand oil, there is also an anti-counterfeiting mark.

Observation oil

The colors of real engine oil and good engine oil are transparent, and there are no impurities and suspended substances. When they are shaken, it can be seen that they have good fluidity and do not agglomerate. If they are fake or inferior engine oils, there may be deposits and opacity, or caking.

smell

Engine oil is generally blended with base oil and additives, and synthetic oil is added with various additives. The smell of synthetic oil is the taste of additives. Therefore, if the engine oil on the market is synthetic oil with mineral oil, it is the most convenient and reliable to identify it by smell. There is a strong sour taste, indicating that the oil has deteriorated and should be replaced.

Try the feel.

If it is good engine oil, you should feel that the engine oil is very smooth and moist. If it is inferior engine oil, it will appear sticky, with particulate impurities, poor viscosity and even astringent taste.

shake

Good engine oil will produce certain bubbles after violent shaking. If the bubbles disappear slowly, it may be inferior engine oil, because good engine oil has good fluidity.

Oil drop tracing method

Take a clean piece of white paper (recommended facial tissue), drop a few drops of engine oil on the paper and observe it later. If the oil is of good quality, it will appear smooth yellow on the paper without powder.