With the popularity of cars, everyone has a basic understanding of car maintenance, that is 5,000 km a maintenance. This 5,000 km of routine maintenance is to replace the filter and oil, check the tires, etc. But a lot of people are giving cars When doing maintenance, generally do not pay attention to car oil is to choose 5w30 or 5w40, the most selected brand is already good. Even a lot of people, directly to the auto repair shop is responsible for all, to pay for the time to pick up the car It can be seen that most car owners, on the car maintenance, especially the car oil is still a small white.
Why do you want to talk about 5W-30 and 5W-40? Because these two models are two kinds of oils that are widely used nowadays, because 5W-30 and 5W-40 have a wide temperature range, they belong to the four seasons universal engine oil, they are both It has low-temperature start-up fluidity and can provide a relatively thick oil film at high temperatures to give better protection to the engine.
The meaning of 'W' can be understood as Winter, the abbreviation of winter. For 5w-30, 5w means the flow performance of oil at low temperature. The smaller the value before W, the better the low temperature fluidity of oil. The lower the applicable minimum temperature; the number behind W refers to the viscosity of the oil at 100 degrees Celsius, and 30 is the high temperature viscosity grade of the oil. The higher the value, the better the engine protection performance of the oil at high temperatures.
30, 40 does not directly represent the temperature, it refers to the viscosity at 100 degrees, and has nothing to do with temperature. 5W-30 means that its kinematic viscosity is 30 at 100 °C.
Compared with 5w-40 and 5w-40, the high temperature viscosity index of 5w-40 is better than 5w-30. Don't underestimate the gap between these 10 indicators. The difference between the two is very important for car maintenance. When the new car is being repaired, try to use the recommended model on the car maintenance manual. For cars with a certain number of years, we should also choose the model of the oil depending on the situation.
First of all, if the car is in good condition, the viscosity of the oil must be selected according to the recommended viscosity in the Car Maintenance Manual, because the technical requirements of the engine designed by each car manufacturer are different, and the viscosity requirements of the oil are also different. Not the same. (Normally, Japanese and Korean cars are recommended to use 20, 30 viscosity oils, such as: SAE0W-20, 0W-30, 5W-20, 5W-30, the US recommended to use 30 viscosity oil, such as: SAE5W-30, European recommended 40-viscosity oil, such as: 0W-40, 5W-40) This car oil difference is still very big, especially Audi cars, must use 5w40 oil. Usually, Japan and South Korea It is recommended to use 20, 30 viscosity oils, such as: SAE0W-20, 0W-30, 5W-20, 5W-30, the US recommended to use 30 viscosity oil.
