What is the difference between 0w20 and 0w30?

[CaliAnn]

The differences between 0w20 and 0w30 are as follows: The viscosity of the oil is different, with 0w30 being more viscous than 0w20; the oil film thickness varies, as 0w30 can form a thicker oil film compared to 0w20, preventing engine cylinder wear and other phenomena; the fuel efficiency differs, with 0w20 being thinner than 0w30, which also means better fluidity, less resistance during machine operation, and better fuel economy. The detailed differences between 0w20 and 0w30 engine oil: The number after the W in the oil grade represents the high-temperature viscosity rating of the oil. This indicates the likelihood of the oil thinning at high temperatures. The larger the number, the higher the viscosity, and the higher the applicable environmental temperature, meaning the oil has better high-temperature stability and fluidity. Therefore, in terms of performance, specifically high-temperature fluidity and stability, 30-grade oil performs slightly better than 20-grade oil, with higher viscosity. The viscosity of engine oil changes with temperature, so special attention is needed to its performance under both low and high temperatures. For example, in 5W-30, the first number indicates low-temperature fluidity, with 5W representing the ability to withstand -30°C. The smaller this number, the better the low-temperature fluidity: 0W is -35°C; 5W is -30°C; 10W is -25°C; 15W is -20°C; 20W is -15°C; 25W is -10°C. This ensures smoother cold starts for the vehicle. The second number represents the kinematic viscosity of the oil at 100°C. The higher the number, the better the oil maintains its viscosity at high temperatures, which can also be understood as better lubrication performance under high temperatures. Relatively, better low-temperature fluidity means smoother cold starts for the vehicle and better engine protection. The viscosity of engine oil should not be too high or too low. If the viscosity is too low, it can increase engine wear. If the viscosity is too high, it can increase resistance during engine operation, leading to reduced power and increased fuel consumption. When the engine is running, the oil forms a film on the surfaces of various engine components, reducing friction between them and lowering the operating resistance within the engine. If the oil viscosity is too low, the oil cannot form a stable film, which can exacerbate engine wear. For fully synthetic oil, the recommended replacement interval is one year or 10,000 kilometers. For semi-synthetic oil, the replacement interval is slightly shorter, requiring a change every 7,000 kilometers or six months. When selecting engine oil, consider the following: Choose oil based on the engine's requirements. It is unnecessary to use overly advanced oil in engines with lower requirements, and lower-grade oil should not be used in engines with higher requirements. Preferably choose multi-grade oil, as it is economical, long-lasting, and efficient, providing better protection for the engine. Due to the characteristics of multi-grade oil, it may appear darker earlier and have lower oil pressure compared to conventional oil, both of which are normal. Since engine oil significantly affects the performance and lifespan of the engine, it is essential to strictly follow the vehicle's manual to select oil of the same series, service grade, and viscosity grade. The oil recommended in the vehicle manual is based on the engine's performance and the regional climate, providing guidance for oil selection and leaving a considerable safety margin.