At present, the engine oil on the market is divided into three types: ordinary mineral oil, semi-synthetic engine oil, and fully synthetic engine oil.
Mineral oil
Mineral oil is one of the more commonly used lubricants on the market. It is used to fractionate useful substances such as gasoline and aerospace oils in the oil refining process, and then to extract and process the remaining base oil. Essentially, it The use of crude oil is a poor component. Mineral oil is cheap, its service life and lubrication performance are not as good as those of synthetic oils, and it also pollutes the environment. In addition, mineral oil cannot be contained during the refining process. Completely removed, so high flow point, not suitable for use in low temperature areas and extreme conditions.
2. Semi-synthetic engine oil
Semi-synthetic engine oil is a semi-synthetic base oil. It is a product purified by hydrocracking technology based on mineral oil. It is a blend of mineral engine oil and fully synthetic engine oil in a 4:6 relationship. Semi-synthetic oil The purity is very close to that of synthetic oil, but its cost is slightly higher than that of mineral oil. It is an ideal transition product of mineral oil to synthetic oil.
3. Synthetic motor oil
Synthetic motor oil is a high-grade oil in the engine oil. It is derived from gas or natural gas dispersed in crude oil, propylene, and then polymerized, catalyzed and other complex chemical reactions to form a macromolecular lubricant. In essence, it uses the better components of crude oil, chemically reacts and achieves the desired molecular form under the control of manpower, and the synthetic oil molecules are arranged neatly, and the ability to resist external variables is naturally strong, so the physical quality is better. Heat stability, anti-oxidation, resistance to viscosity changes are naturally much stronger than mineral oils and semi-synthetic oils, so the price is also the highest.
Oil index
There are two main indicators of oil: API quality index, SAE viscosity index.
1.API quality indicators
The beginning of 'S' stands for petrol engine oil, specifications are: APISA, SB, SC, SD, SE, SF, SG, SH, SJ, SL, SM, SN. From 'SA' up to 'SN' Letters, the level of oil will be better than the former, the higher the level behind the mother, the highest level of the current 'SN' level.
2.SAE viscosity index
The meaning of the SAE label, SAE is the English "Automotive Engineers Association" abbreviation. SAE label behind the marked oil viscosity value, such as: SAE5W-40, where 'W' represents WINTER days, 'W' in front of the number represents the low temperature In the case of flow viscosity, the smaller the value, the better the low temperature fluidity of the engine oil. The better the protection of the engine when the vehicle is cold-started; the figure after the 'W' is the viscosity of the oil at 100°C. The higher the high viscosity, the better the protection of the engine at high temperatures.
Oil selection method and summary:
The choice of oil is very particular. When choosing the oil, the owner can choose the local maximum and minimum temperature, vehicle grade and vehicle condition to select. If the oil with too much viscosity is used, it will increase the resistance of the engine and affect the engine power; If the viscosity of the oil is too low, the lubrication quality will not be guaranteed and the wear of the engine will be exacerbated. For engines with relatively large wear and tear, which have larger clearances, a higher viscosity oil may be used to enhance the sealing performance of the mating parts. The point is that the new car chooses a lighter amount of engine oil, while cars with a higher number of kilometers use a higher viscosity oil.
The choice of oil is not the more expensive the oil is, the better it is. If you really can't use it properly, you can refer to the car's User Manual and you can't go wrong. However, there is a principle that must be followed, that is, the choice of oil can be improved. Grade, but cannot be reduced. For example, the original loading oil is full synthetic oil, 10,000 kilometers for oil, you can not choose mineral oil, a change of 5000 kilometers, this is obviously not suitable. In short, suitable for you, is the best.
Synthetic engine oil is not suitable for any vehicle. Semi-synthetic engine oil is recommended for old cars. Because the old car's sealability is relatively poor, and the full synthetic oil has low viscosity and fluidity, it is easy to cause oil leakage. Under such circumstances, it is more appropriate to choose a semi-synthetic engine oil with high viscosity.
