What does the 'W' in motor oil stand for?
2 Answers
Motor oil with a 'W' indicates that the oil can be used normally in winter, where 'W' is the abbreviation for 'winter'. Common motor oil grades include: 5w30, 5w40, 0w30, 0w40, etc. The number before the 'W' represents the oil's low-temperature flow performance. 5w means the oil can flow normally at -30 degrees Celsius, while 0w means the oil can flow normally at -35 degrees Celsius. Motor oil, also known as engine lubricant, serves functions such as lubrication and friction reduction, auxiliary cooling, sealing and leak prevention, rust and corrosion protection, and shock absorption. It is often referred to as the 'blood' of a car.
Speaking of the 'W' in motor oil grades, let me explain it in detail. This 'W' is actually an abbreviation for 'Winter' in English, meaning winter. It mainly reflects the fluidity of the oil in low-temperature environments. For example, in the commonly seen 5W-30, the number before the 'W' represents the low-temperature viscosity grade. The smaller the number, the less likely the oil is to solidify in cold weather, providing better protection during cold starts. The number after the 'W' is the high-temperature viscosity grade, where a larger number indicates that the oil can maintain sufficient oil film strength even at high temperatures. Therefore, when choosing motor oil, you need to consider your local climate conditions. In areas with particularly cold winters, you should choose an oil with a smaller number before the 'W'.
