What is the difference between 0W-40 and 5W-40?
3 Answers
5W-40 and 0W-40 are both oil grades, and the only difference between them is their resistance to external low temperatures: 5W in 5W-40 oil represents a resistance to external low temperatures of -30°C; 0W in 0W-40 oil represents a resistance to external low temperatures of -35°C. Below is more information about oil grades: 1. Oil grades include two parts: classification and viscosity specifications. Oil grades usually indicate viscosity and quality. The viscosity of lubricating oil is often identified using SAE grades, where SAE is the abbreviation for the "Society of Automotive Engineers" in English. 2. The number following the oil classification indicates its viscosity specification. The smaller the number before the W, the better the oil's low-temperature fluidity, meaning it can be used in lower environmental temperatures and provides better engine protection during cold starts. 3. The number after the W represents the oil's kinematic viscosity at 100°C. The higher the number, the higher the viscosity.
The main difference between 0W-40 and 5W-40 lies in their low-temperature viscosity, which affects cold-start performance. Last time I tested at minus ten degrees Celsius, 0W-40 allowed faster engine starts in severe winter, with smoother oil flow, reduced startup friction, and less engine wear—making it particularly suitable for northern or cold regions. In comparison, 5W-40 works fine in slightly warmer weather but may start slower below zero degrees, potentially increasing fuel consumption slightly. Both oils share the same normal-temperature viscosity of 40, so long summer drives show little difference. Personally, I prefer 0W-40, especially during seasonal transitions—it offers better engine noise control and an overall smoother feel. However, always check your car manual’s recommendation; some older vehicles run more cost-effectively on 5W-40. Don’t just chase high performance while overlooking actual needs and budget. Choosing the right oil daily extends engine life and saves fuel—worth it!
From an automotive enthusiast's perspective, both 0W-40 and 5W-40 are called multi-grade engine oils, with the numbers representing viscosity characteristics. The 0W portion indicates superior fluidity at low temperatures (around -35°C), providing instant protection for engine components during cold starts. The 5W performs slightly less effectively at -30°C but may offer better fuel economy. Both have the same high-temperature viscosity of 40, so there's not much difference in driving feel. Based on my personal experience, if you frequently take long trips or drive aggressively, choosing 0W-40 can reduce cold-start wear and protect turbo components. However, for normal, gentle driving in moderate climates, 5W-40 is sufficient. Remember to regularly check your oil condition and match it to local weather conditions when changing seasons—don't force a mismatch just to save money, or you'll be wasting it.
