What is the difference between engine oil 20 and 30?
2 Answers
The viscosity of engine oil differs, as does its sealing performance. Below is a detailed explanation of the differences between engine oil 20 and 30: 1. Different oil viscosity: The primary difference between 5W30 lies in the high-temperature viscosity of the oil. The distinction between 5W-20 and 5W-30 is merely the difference in the latter numbers. 5W20 has lower viscosity (ranging between 5.6-9.3), which is relatively more fuel-efficient and provides a lighter driving feel. On the other hand, 5W-30 has higher viscosity (ranging between 9.3-12.5), which is relatively more fuel-consuming and makes the throttle feel heavier, but results in quieter engine noise. 2. Different sealing performance: The higher the viscosity, the better the sealing performance. For engine oils 5W30 and 5W20, the number after the W represents the high-temperature viscosity. Therefore, 5W30 has better sealing performance than 5W20. However, a higher number is not always better, as higher viscosity leads to greater friction and consequently greater power loss in the engine.
I'm the most qualified to speak on this matter, as my car has experienced both types of oil. The numbers 20 and 30 after the W represent high-temperature viscosity—the higher the number, the thicker the oil becomes when the engine heats up. The 20-weight oil has better fluidity, lubricating parts quickly like water during cold starts, making it particularly suitable for new cars. Last time I switched to 20-weight oil on the highway, I clearly felt the throttle become lighter, and the fuel gauge dropped more slowly. However, the 30-weight oil offers better high-temperature protection, giving more peace of mind for older cars. Once, I drove a friend's 8-year-old SUV after switching to 30-weight oil, and the engine sound became noticeably more stable. Which one to choose depends on your car's manual—never switch viscosity based on assumptions.
