The main difference between diesel engine oil and gasoline engine oil lies in the viscosity of the oil. It is important to understand that diesel engines operate under relatively harsh conditions, requiring stronger oil film strength (on the friction pair surface). Therefore, diesel engine oil has a higher viscosity, as otherwise it would not be able to ensure proper engine lubrication.

Secondly, the difference in engine oil additives. During the combustion process of diesel engines, sulfuric acid or sulfurous acid is formed. Once it enters the oil pan, it will naturally affect the performance and lifespan of the engine oil. Therefore, diesel engine oil requires more antioxidants and anti-corrosion additives.