What is the difference between four-stroke engine oil and automotive engine oil?
2 Answers
Here are the differences between four-stroke engine oil and automotive engine oil: 1. Structural aspect: In automotive engines, the engine is lubricated separately from the transmission and clutch, with the oil temperature in the crankcase ranging between 75-90°C; whereas in four-stroke engines, components such as the wet multi-plate clutch, high-speed and transmission gears, shift mechanism, as well as moving parts like pistons, cylinders, and intake/exhaust valves, are all housed within the same structure, sharing the same volume of oil. Moreover, the friction plates of the clutch and the rotation of transmission gears generate significant heat, causing the oil temperature in the crankcase to reach as high as 80-120°C. 2. Cooling effect aspect: The oil capacity of an automotive engine is approximately 5-7L, while that of a four-stroke engine is only about 1L. Oil must flow sufficiently to perform its cooling and other functions. The amount of oil significantly affects the cooling performance. Additionally, most four-stroke engines are generally air-cooled, which offers much poorer cooling efficiency compared to the radiator circulation cooling in automobiles. Even water-cooled engines have inferior heat dissipation due to their smaller water capacity compared to automobiles. This inevitably results in the oil temperature of four-stroke engines being significantly higher than that of automotive engine oil.
Regarding the difference between four-stroke oil and automotive engine oil, I can briefly share from my years of driving experience. Generally speaking, four-stroke oil is a generic concept, meaning oil suitable for four-stroke engines, which can be used in motorcycles or equipment like lawn mowers, while automotive engine oil is specifically designed for car engines. The main differences lie in their formulations. For example, automotive engine oil often contains more anti-wear additives and detergents because car engines operate at higher speeds and under greater loads, requiring stronger oil stability. I’ve tried using four-stroke oil in my car a few times and noticed unstable oil pressure and increased noise. Later, I realized this could lead to premature engine wear, so it’s best to follow the car manual’s recommendations and avoid mixing oils to save money. Automotive engine oil also has more precise viscosity grades to suit different climates. In short, the core point is that automotive engine oil is a specialized product for specific brands, while four-stroke oil is a general term—using the wrong one can easily cause problems.
