What Type of Engine Oil Should Japanese Cars Use After 100,000 Kilometers?

[MacBrantley]

For Japanese cars after 100,000 kilometers, it is recommended to use 5W-30 full synthetic engine oil. The functions of engine oil are introduced as follows: Lubrication and Wear Reduction: There is rapid relative sliding between the piston and cylinder, as well as between the main shaft and bearing shells. To prevent excessive wear of parts, an oil film must be established between the two sliding surfaces. A sufficiently thick oil film separates the relatively sliding part surfaces, thereby reducing wear. Cooling: Engine oil can carry heat back to the oil tank and then dissipate it into the air, helping the radiator cool the engine. Cleaning: High-quality engine oil can carry carbon deposits, sludge, and worn metal particles from engine parts back to the oil tank through circulation. The flow of the lubricating oil washes away contaminants generated on the working surfaces of the parts.