What are the differences between 0w40 and 5w40 engine oil?
4 Answers
The differences between 0w40 and 5w40 engine oil are: Different low-temperature fluidity: 0w40 engine oil has better low-temperature fluidity and can adapt to lower temperatures, down to -35 degrees Celsius; 5w40 engine oil can only withstand temperatures as low as -30 degrees Celsius. Different types of engine oil: 0w40 engine oil refers to fully synthetic oil; 5w40 engine oil refers to semi-synthetic oil. The number before the W represents the lowest temperature it can withstand. The smaller the number, the lower the low-temperature viscosity, the better the low-temperature fluidity, the lower the applicable minimum temperature, and the easier it is to start in cold weather. The number after the W represents the viscosity of the oil at 100 degrees Celsius. The larger the number, the higher the viscosity, and the better the oil film formation at high engine temperatures, making it suitable for a wider range of temperatures.
It's freezing cold here in winter, often dropping to minus 30 degrees. I frequently use 0W40 oil, which has excellent fluidity in ultra-low temperatures, being as thin as water, allowing the engine to start quickly and smoothly. In contrast, 5W40 oil feels a bit sticky at the same temperature, resulting in slower starts and potential engine damage like cylinder scoring. Both oils have the same high-temperature viscosity, protecting the engine during normal operation, but 0W is slightly more fuel-efficient in extremely cold regions, even though it's a bit more expensive. It's also crucial to consider what oil your car is suited for—don't switch randomly. My neighbor once used the wrong 5W oil in the northeast and nearly ruined his engine, and the repair costs weren't cheap. Choosing the right oil based on the season and local temperatures can extend your car's lifespan and reduce unexpected issues.
I used to work in auto repair, and customers often asked about the difference between these two oils. Actually, the main distinction between 0w40 and 5w40 lies in cold-start performance: 0w can still pump smoothly at -35°C, preventing wear, while 5w performs slightly worse at -30°C, making it more suitable for milder climates. At high temperatures, both have the same viscosity, offering similar protection. However, 0w is more fuel-efficient in cold conditions, reducing fuel consumption. I recommend choosing oil based on your location—use 0w in the north and 5w in the south. Don’t skimp to save money, as engine damage will cost more to repair. Also, check your vehicle’s manual, as some high-revving engines are sensitive to viscosity.
I prioritize energy efficiency and environmental protection, and have compared the impact of different engine oils. 0W40 has higher fluidity at low temperatures, reducing engine startup resistance and saving approximately 5% on fuel; 5W40 is slightly more viscous, resulting in marginally higher fuel consumption, but the difference is minimal. Both provide the same level of high-temperature protection. Using 0W in winter can reduce emissions, while 5W is sufficient for summer or warmer regions. It's important to match the oil grade to your vehicle, as incorrect viscosity may accelerate wear. Making a reasonable choice can save money and protect your car.
