What does the engine oil grade 5w30 mean?
2 Answers
The engine oil grade 5w30 refers to the viscosity specification of the oil, which consists of three main parts: W, the number before W, and the number after W. The number before W is 5, and the smaller this number, the better the oil's flowability at low temperatures, indicating a lower applicable minimum temperature. The number after W is 30, which represents the oil's viscosity at 100 degrees Celsius. A higher number indicates higher oil viscosity, better high-temperature resistance, and superior high-temperature protection performance. 5W30 is particularly suitable for Japanese and Korean cars, as their engines are more precise with smaller clearances. In terms of viscosity alone, 5W30 is more suitable for colder regions and winter seasons.
I've been driving for many years and know that the 5W30 oil grade is a common and practical specification. The '5W' indicates the winter viscosity—the lower the number, the easier it flows in cold weather. For example, even at -20°C, it can quickly lubricate the engine, ensuring smooth starts without harming the machine. The '30' refers to the high-temperature viscosity, where the number represents the oil's ability to maintain a certain thickness in hot weather, protecting internal engine components from wear. This combination strikes a perfect balance, making it suitable for regions with distinct seasons or most household cars. I once tried using 10W40 in winter, but it resulted in difficult starts and increased fuel consumption. So now, I strictly follow the user manual for oil changes, replacing synthetic oil approximately every 7,500 kilometers to keep the engine quiet, fuel-efficient, and durable. Don't underestimate the importance of this grade selection—it significantly impacts the car's lifespan. Always verify the oil's authenticity with a technician during maintenance.
