What are the differences between 5W and 10W engine oils?
2 Answers
5W and 10W refer to low-temperature viscosity, and the smaller the number before the W, the better the low-temperature fluidity of the engine oil, the lower the minimum temperature it can adapt to, and the stronger its cold resistance. Therefore, there are two main differences between 5W and 10W engine oils: 1. 5W engine oil has better low-temperature fluidity than 10W, making it easier to start in low-temperature environments. 2. 5W engine oil can be used at a minimum temperature of -30°C, while 10W can only be used at a minimum temperature of -25°C. 5W engine oil has stronger cold resistance than 10W. Here’s how to specifically choose the right engine oil type: 1. For normal driving conditions, such as in Japanese cars, 0W20 is sufficient. In higher climate temperatures, switching to 0W30 or even 0W40 is enough, as Japanese cars require engine oil with sufficient fluidity. 2. For current German and European car engines, all-season engine oils can be used universally. Common 5W30 can basically meet the needs, and 5W40 is generally suitable for domestic environments.
Having driven for over a decade, I've found the main difference between 5W and 10W motor oil lies in low-temperature fluidity. 5W oil can start easily even at -30°C with excellent fluidity, lubricating critical engine components instantly during cold starts to reduce wear. 10W oil struggles below -25°C, making it more suitable for warmer southern regions. Both offer similar protection at high temperatures, but 5W provides slightly better fuel efficiency due to lower cold-start resistance, saving money long-term. However, 5W typically costs about 20% more. If you're in Guangdong or Hainan, 10W is perfectly adequate without overspending. Northern drivers should still opt for 5W for peace of mind – the smoother winter morning starts are particularly noticeable.
