What is the difference between 5w30 and 10w40 engine oil?
2 Answers
The differences between 5w30 and 10w40 engine oil are as follows: Different applicable temperatures: The freezing point temperature corresponding to 5W oil is -30°C, while that of 10W oil is -20°C. 5W30 oil has better cold resistance than 10W40, can be used at lower temperatures, and provides better cold-start performance. Different oil viscosity: The numbers 30 and 40 indicate the high-temperature viscosity of the oil. 10W40 oil has higher viscosity than 5W30, offering better high-temperature protection and sealing performance. However, higher viscosity does not necessarily mean better performance. Excessive viscosity can increase engine operating resistance, leading to insufficient engine power and increased fuel consumption.
I'm an ordinary office worker driving an economy car. When changing the oil, the mechanic suggested that 5W30 starts up faster in winter and protects the engine from wear, while 10W40 is thicker in summer heat for better lubrication, making it suitable for long trips. The specific difference is that a smaller number before the W, like 5, means it flows better in cold weather, while a larger number after the W, like 40, withstands heat better in hot weather. I tried using 10W40 in sub-zero temperatures, and it took forever to start, but switching to 5W30 made it much smoother. If you live in a warm place like the south, 10W40 lasts longer, but always check the vehicle manual's recommendation—otherwise, you might waste fuel or damage parts. Changing the oil on time is key to avoid breaking down mid-drive and disrupting daily life.
