What is SF15W-40 engine oil?

[Rodger]

SF is the grade designation of engine oil, and 15W-40 is the viscosity rating of the oil. Engine oil grades range from "SA" to "SN", with each subsequent letter indicating better performance and more additives to protect the engine. The further the letter is in the alphabet, the higher the quality grade. International brands often have oil grades above SF. 15W-40 is the viscosity rating of the oil. Below is some relevant information about engine oil: 1. Function of engine oil: Engine oil lubricates and reduces wear, assists in cooling, seals against leaks, prevents rust and corrosion, and provides shock absorption. It is known as the "blood" of a car. Choosing the right oil and changing it regularly can maintain the engine in good condition and extend its service life. 2. Choosing engine oil: The best oil is not necessarily the most expensive; it should be selected based on the characteristics of the car's engine and driving habits. It can also be categorized by winter and summer use. For winter, the primary consideration is the low-temperature viscosity grade, while in summer, due to higher temperatures, oils with better low-temperature viscosity grades are not necessary.