What is the difference between fully synthetic 5w30 and 5w40?
1 Answers
The difference between fully synthetic engine oils 5w30 and 5w40 is: The smaller the number before W, the lower its low-temperature viscosity, the better its low-temperature fluidity, and the lower the applicable minimum temperature. The larger the number after W indicates the higher the viscosity of the engine oil. The number after W mainly refers to the indicator of the oil's high-temperature resistance; the larger the number, the better the protective performance of the oil at high temperatures. Here are methods for choosing engine oil: 1. Based on vehicle age: Generally, referring to the vehicle maintenance manual, new cars should choose oil with slightly lower viscosity, where 5W30 would be more suitable. 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, where 5W40 would be more appropriate. 2. Based on road conditions: Road conditions can greatly affect the lifespan of engine oil. In areas with poor road conditions, the oil change interval should be shortened. In urban areas with frequent traffic congestion leading to frequent stops while driving, it is recommended to use oil with lower viscosity. If you frequently drive long distances or on highways, slightly higher viscosity is recommended. 3. Based on temperature: Due to significant temperature differences between summer and winter, oil pressure gauges generally read lower in summer. However, as long as it is within the reasonable range specified in the manufacturer's manual, it is normal, and car owners should not be overly concerned. If the oil pressure gauge is unusually high or low, deviates too much from the normal situation, or is outside the reasonable range, then a thorough inspection is needed to check if there are any issues with the engine, such as a faulty sensor, clogged oil passage, etc.
