A single-grade engine oil is defined by SAE J300. SAE J300 has established eleven viscosity grades, of which six are considered Winter-grades and given a W designation. The 11 viscosity grades are 0W, 5W, 10W, 15W, 20W, 25W, 20, 30, 40, 50, and 60. A single-grade engine oil is suitable for only one season, like summer. no low-temperature viscosity index requirement. In the market, SAE 30, SAE 40, SAE 50 is the usual oil grade. Multi-grade engine oil is suitable for 4 seasons. It has strict requirements for low-temperature viscosity index. It can be used in specific area, no need to change oil because of different seasons. Main viscosity grades are 10w-30, 15w-40, 10w-40, 20w-50. Multi-grade oil possesses great start property in cold weather. Comparing with single-grade oil, it has excellent fuel-saving property, usually saving 1.0% ~ 3.0 % fuel.
December 26th, 2017