What is the difference between 5w and 10w engine oil?
3 Answers
The grade after the engine oil classification indicates its viscosity specification. The smaller the number before 'w', the better the low-temperature fluidity of the engine oil. The following are the differences between 10w and 5w engine oils: 1. Different low-temperature viscosity; 10w engine oil: The low-temperature viscosity of 10w engine oil is worse than that of 5w engine oil, with poorer low-temperature fluidity and a higher applicable minimum temperature. 5w engine oil: The low-temperature viscosity of 5w engine oil is better than that of 10w engine oil, with better low-temperature fluidity and a lower applicable minimum temperature. 2. Different applicable maximum temperatures; 10w engine oil: The applicable maximum temperature of 10w engine oil is higher than that of 5w engine oil, with a larger applicable temperature range. 5w engine oil: The applicable maximum temperature of 5w engine oil is lower than that of 10w engine oil, with a smaller applicable temperature range. 3. Different wear reduction effects. 10w engine oil: The wear reduction effect of 10w engine oil on parts is better than that of 5w engine oil. 5w engine oil: The wear reduction effect of 5w engine oil on parts is worse than that of 10w engine oil.
I think the main difference between 5W and 10W engine oil for daily driving lies in cold-weather starts. In the northern regions where winters are cold, 5W has better fluidity, allowing the engine to start and lubricate faster, preventing morning struggles due to freezing. On the other hand, 10W has a slightly higher viscosity, resulting in weaker low-temperature flow, which might lead to louder engine noise during startup. In summer, both perform similarly, with no noticeable impact on power or fuel efficiency. I used to save money by using 10W in my old car, but after switching to 5W, I noticed smoother operation. When choosing engine oil, don’t just focus on this number—always refer to your car’s manual for the recommended viscosity standard, such as 5W-30. Remember to change the oil every 5,000 miles to maintain cleanliness and ensure the engine runs healthily. During extreme temperature changes, using high-quality oil reduces the risk of breakdowns.
In my decades of car repair experience, I've seen many oil-related issues. The main difference between 5W and 10W lies in their low-temperature performance. The 'W' stands for winter, and a smaller number like 5W indicates better cold resistance, allowing smooth starts at -30°C; 10W performs slightly worse, around -25°C. Modern car engines are more precise, so 5W is recommended for better fuel efficiency; older vehicles or trucks might still use 10W. The actual driving impact is minimal as long as the overall viscosity suits your car, like 5W-30 meeting the requirements. The key isn't obsessing over the grade but sticking to oil changes every six months to prevent impurity buildup. Engine protection comes first—randomly switching oils can harm your car.
