How are motor oil grades classified?

[LaSilas]

Motor oil grades are classified as follows: 1. Oil grades are represented by a combination of two letters. The S-series represents oils for gasoline engines, with specifications ranging from SA to SN in alphabetical order (excluding SI), incrementing by one letter each time; 2. The C-series represents oils for diesel engines. If both S and C letters are present, it indicates that the oil is suitable for both gasoline and diesel engines. When selecting motor oil, you can refer to the vehicle maintenance manual, which usually specifies the required oil grade. Choose high-quality oil produced by reputable manufacturers, preferably specifically formulated for your vehicle. Avoid using counterfeit or substandard oils, as they can accelerate engine wear and shorten the engine's service life.