What are the differences between 0w40 and 5w40 engine oil?
2 Answers
The differences between 0w40 and 5w40 engine oil are: 1. Different low-temperature fluidity: 0w40 engine oil has better low-temperature fluidity and can adapt to lower temperatures, down to -35 degrees Celsius; 5w40 engine oil can only withstand temperatures as low as -30 degrees Celsius. 2. Different types of engine oil: 0w40 refers to fully synthetic oil; 5w40 refers to semi-synthetic oil. The number before the W represents the minimum temperature it can withstand. The smaller the number, the lower the low-temperature viscosity, the better the low-temperature fluidity, and the lower the applicable minimum temperature, making it easier to start in cold conditions. The number after the W represents the viscosity of the oil at 100 degrees Celsius. The larger the number, the higher the viscosity, which means it can form a good oil film at high engine temperatures and has a wider applicable temperature range.
I previously did extensive research on these two types of engine oil when driving in northern China. The biggest difference between 0W40 and 5W40 lies in the number before the "W". 0W has significantly better low-temperature fluidity than 5W, maintaining lubrication even at -35°C. In northeastern China where winter temperatures drop below -20°C, using 0W40 makes cold morning starts noticeably smoother, preventing the engine from straining. The difference in summer is minimal, as both offer good high-temperature protection. However, 0W40 is considerably more expensive. If you're in southern China where winter lows are around 0°C, 5W40 is completely sufficient and more economical. Just remember to always use the viscosity grade specified in your vehicle's manual – never make arbitrary changes.
