What is the SM grade of engine oil?
1 Answers
SM is one of the quality grades of engine oil, ranking third after SN and SP grades. SM-grade engine oil includes both synthetic and mineral oils, such as LIQUI MOLY oil which is API SM grade. More details are as follows: 1. The API quality grade represents the quality level of engine oil, using simple codes to describe the working capability of engine oil. In the API quality grade, engine oil is divided into the S series and C series. The S series is specialized oil for gasoline vehicle engines, with grade levels including SA, SB, SC, SD, SE, SF, SG, SH, SJ, SL, SM, SN, and SP, while the C series is specialized oil for diesel vehicles. 2. Whether it is gasoline or diesel engine oil, as the letter in the quality grade designation moves further in the alphabet, the grade improves sequentially, with the oil quality and performance becoming more superior. 3. When selecting engine oil, in addition to the viscosity grade, the quality grade is also an important indicator. Generally, the grade recommended in the maintenance manual or for the engine model is sufficient. However, if frequently driving in congested traffic conditions, it is advisable to use a higher grade of engine oil, which is more environmentally friendly and economical. Nevertheless, vehicle owners do not necessarily need to pursue the highest grade of engine oil, as while the oil quality and performance may be relatively superior, the price will also increase accordingly.