The number after W indicates the kinematic viscosity of engine oil at 100℃. The higher the number, the greater the viscosity, which means it is better and more stable at high temperature, that is, it is less likely to be diluted at high temperature. That is, 5w40 is more stable than 5w30 at high temperature.
2. Use different objects
The viscosity of 5w40 is better than that of 5w30, so it is more suitable for old cars. 5w30 can effectively reduce fuel consumption, make the engine dissipate heat faster and better, and at the same time, it has low noise, so it is suitable for new cars or naturally aspirated engines.
The symbol w stands for winter.
The smaller the number before W, the smaller the low-temperature viscosity, the better the low-temperature fluidity and the lower the applicable minimum temperature.
Mainly: 0W, 5W, 10W, 15W, 20W, 25W.
0 means it can be used above -35℃, 5 means it can be used above -30℃, and so on, and 25 means it can be used above-10℃.
The 5w30 engine is quieter.
Extended data:
Considering the normal wear and tear of the engine, the clearance of the mating surface becomes larger, and the viscosity of the engine oil will gradually increase with the increase of the age of the vehicle. Generally, it is recommended to use thinner engine oil for vehicles within 50,000 kilometers. After 50,000 kilometers, slowly increase the viscosity of the engine oil, which is also the most suitable protection for the engine.
The engine oil products used in many models are basically four-season general oil, and usually private cars do not need special viscosity. However, in view of the different urban climate conditions, we can consider replacing 40 viscosity products in summer and using 30 viscosity products in winter to provide better protection for vehicles in different temperature environments.
When the car works in the city, the idle time is long, the fuel in the engine cylinder is not fully burned, and there are more sludge and carbon deposits in the engine. Especially in summer, it is suggested that the oil change cycle can be shortened appropriately.
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