What does engine oil 5w30 mean?
2 Answers
W stands for winter. The number before W is 5. The smaller the number, the better the fluidity of the oil at low temperatures, and the lower the applicable minimum temperature. 5W means it can be used at temperatures above -30℃. The number after W is 30, which refers to the viscosity of the oil at 100℃. The larger the number, the higher the viscosity of the oil, the stronger the ability to withstand high temperatures, and the better the high-temperature protection performance. Here is some relevant information: 1. From the perspective of vehicle brands, 5W30 is more suitable for Japanese and Korean cars, as the engines of these two series of vehicles are more precise and have smaller gaps. If we only look at the viscosity grade, 5W30 is more suitable for colder regions and winter. 2. For fully synthetic oil, it is generally recommended to change it every 10,000 kilometers or one year; for semi-synthetic oil, it should be changed every 7,500 kilometers or seven to eight months; for mineral oil, which has relatively poorer performance, the replacement cycle should be shortened accordingly, and it should be changed every 5,000 kilometers or six months.
The '5W' in 5W30 engine oil indicates good fluidity at low temperatures, especially during cold winter starts, allowing the engine to run smoothly and reducing wear. The '30' signifies maintaining appropriate viscosity under high-temperature conditions, preventing oil film breakdown and ensuring stable lubrication. This type is a multi-grade oil suitable for most climates and vehicle models. I generally recommend car owners choose based on their driving environment—5W is better for cold northern regions to prevent freezing, while ensuring high-temperature protection in hot southern areas. Oil quality directly affects engine lifespan and fuel consumption; choosing the wrong type may lead to performance decline or premature overhaul. Regularly checking the oil condition and replacing it every 5,000-7,500 kilometers as recommended in the manual can extend engine durability. Simply put, it acts like an engine's protective umbrella, balancing energy efficiency and peace of mind.