What is the difference between synthetic engine oils 5w30 and 5w40?
1 Answers
The difference between fully synthetic engine oils 5w30 and 5w40 is: 5w40 offers better protection at high temperatures compared to 5w30. The smaller the number before the 'W', the lower the viscosity at low temperatures, the better the low-temperature fluidity, and the lower the applicable minimum temperature. The larger the number after the 'W', the higher the viscosity of the oil. The number after 'W' mainly refers to the oil's high-temperature resistance index; the larger the number, the better the oil's protective performance at high temperatures. 5w40 provides better high-temperature protection than 5w30. Below are detailed guidelines for selecting engine oil for cars: 1. Based on vehicle age: Generally, while referring to the vehicle's maintenance manual, new cars should choose oil with slightly lower viscosity. As the vehicle ages, choose oil with slightly higher viscosity. Older car engines experience more severe wear, thus requiring relatively higher viscosity oil for smoother and more comfortable driving. 2. Based on road conditions: Road conditions can significantly affect the lifespan of the oil. In areas with poor road conditions, the oil change interval should be shortened. In urban areas where traffic congestion is frequent, leading to frequent stops while driving, it is recommended to use oil with lower viscosity. If you frequently drive long distances or on highways, it is advisable to use oil with slightly higher viscosity.
