What does SM grade engine oil mean?
1 Answers
SM grade engine oil refers to the API engine oil quality classification. API is the abbreviation for the American Petroleum Institute. The API classification represents the quality grade of engine oil, using simple codes to describe the working capability of engine oil. Engine oil grades are divided into SA, SB, SC, SD, SE, SF, SG, SH, SJ, SL, SM, and SN levels, with higher grades indicated by letters further in the alphabet. Among international brands, engine oil grades are mostly above SF level. The C-series represents oil for diesel engines. If both S and C letters are present, it indicates that the oil is suitable for both gasoline and diesel engines. Different quality grades of engine oil vary in terms of lubrication quality, cooling effect, oil film toughness, thermal stability, and anti-degradation capability.