Should Japanese cars use 0w20 or 5w30?

[VonJames]

Japanese cars can use 0w20 because the engines in Japanese cars have a precise structure, with smaller gaps between the piston rings and cylinder walls, and the piston skirts are designed with molybdenum plating to reduce the friction coefficient. The symbol 'w' stands for winter, which is an abbreviation of 'Winter'. The number before 'w' represents the low-temperature flow performance of the oil. The smaller the number, the better the cold resistance; the larger the number, the weaker the cold resistance. Engine oil, known as the 'blood' of a car, serves to lubricate, clean, cool, seal, and reduce wear in the engine. The viscosity standard adopts the SAE viscosity classification, which is used to distinguish the different temperature ranges suitable for the lubricating oil. The performance standard mainly adopts the API performance classification, which is used to distinguish the performance and quality of the lubricating oil.