Multi-grade oil selection The multi-grade oil viscosity range can span several viscosity grades and can be used in four seasons in a given area. This has good low temperature and high temperature starting performance, can improve engine wear and save fuel and oil. At present, it has been widely used in foreign countries, and the application of multi-grade oil in the country is becoming increasingly widespread. According to the temperature range of the annual maximum temperature and minimum temperature in the area where the engine is used, a suitable four-stage general-purpose multi-grade engine oil can be selected to avoid the trouble of changing oil in winter and summer seasons and in different regions. The choice of oil quality grade, according to the thermal conditions of the engine, the oil quality of the four-stroke gasoline engine is mainly selected according to the compression ratio of the gasoline engine. The greater the compression ratio, the greater the heat load, and the higher the temperature, the higher the oil quality level. The general compression ratio is greater than 7.0, the choice of SC grade oil; compression ratio of 7.08.0, optional SD grade oil; compression ratio greater than 8.0, the choice of SE or SE or higher grade oil; compression ratio of 10 or more, can SF, SG, SH and other high quality oils are selected. The quality grade of diesel engine oil is mainly selected according to the thermal conditions of the diesel engine. The thermal condition of a diesel engine is an important factor that affects the quality of the oil. The greater the diesel engine load, the higher the operating temperature, and the greater the boost ratio, the greater the tendency of engine oil coking and oxidative deterioration, so the quality grade of the selected engine oil should be higher. The thermal conditions of a diesel engine are mainly represented by the strength coefficient of the diesel engine. If the enhancement coefficient is less than 50, use CC grade oil; if the enhancement coefficient is between 50 and 80, choose CD grade engine oil; if the enhancement coefficient is more than 80, use CE or CF grade engine oil. hand water pump,High Quality hand water pump,hand water pump Details, CN Botou Honghai Pump Co.,Ltd , https://www.pumphonghai.com