What is the difference between fully synthetic 0w40 and 5w40?
2 Answers
The difference between 0W40 and 5W40 engine oil lies in their low-temperature fluidity. Due to this, 0W40 performs better than 5W40, offering superior cold resistance. Here are some additional details: 1. The meaning of the number before W: W stands for Winter in English, indicating that this oil is suitable for winter use. The presence of numbers after W means the oil is suitable for both winter and summer. The number before W represents the lowest temperature the oil can withstand. A smaller number indicates lower low-temperature viscosity, better low-temperature fluidity, and suitability for lower minimum temperatures, making it easier to start the engine in cold conditions. 2. The meaning of the number after W: The number after W represents the oil's viscosity at 100°C. A higher number means higher viscosity, which allows the oil to form a better protective film at high engine temperatures and makes it suitable for a wider range of temperatures.
I've been driving for almost 20 years and have some insights about engine oil. Both 0w40 and 5w40 are fully synthetic oils, with the main difference being their performance in cold weather. The smaller number in 0w indicates it flows faster at low temperatures, providing better engine protection during cold starts, especially suitable for areas below -25°C. 5w is slightly inferior, only effective down to around -30°C, and might make winter starts a bit tougher. However, at high temperatures, both oils have the same 40 viscosity, performing equally smoothly in summer. Driving from Beijing to Harbin, I've used both; 0w40 is noticeably more reliable in the north, with quieter engine sounds. In the south, 5w40 is sufficient and can save some money. The choice depends on the weather and your car—don't generalize. The car manual often provides recommendations. Using the wrong oil long-term can increase wear, so always consult a mechanic during oil changes.
