What is the introduction of lubricating oil viscosity?
2 Answers
The viscosity grade of engine oil is closely related to the vehicle model and local temperature. Below is an introduction to its connection with vehicle models and local temperatures: 1. Vehicle model: Japanese cars prefer low-viscosity oil, while German cars prefer high-viscosity oil. 2. Local temperature: (1) 0W suitable temperature — -35°C (polar regions) (2) 5W suitable temperature — -30°C (northeast and northwest regions) (3) 10W suitable temperature — -25°C (north-central and southwest regions) (4) 15W suitable temperature — -20°C (north-central and southwest regions) (5) 20W suitable temperature — -15°C (areas south of the Yellow River and north of the Yangtze River) (6) 25W suitable temperature — -10°C (subtropical regions)
I've been driving for over a decade and choosing oil viscosity is quite particular. Simply put, viscosity refers to how easily the oil flows. For a grade like 5W-30, the number before the W represents low-temperature fluidity—the smaller the number, the smoother the cold starts. The number after the W indicates high-temperature viscosity—the larger the number, the thicker the oil film. I usually use low-viscosity oil like 0W-20, which ensures quick starts in winter, better fuel efficiency, and quieter engine noise on highways. However, older cars need higher viscosity oil like 10W-40, otherwise, poor sealing can lead to oil burning. Last year, I helped a neighbor check his car—he had used the wrong viscosity oil, which caused a spike in fuel consumption and triggered a warning light. Nowadays, new engines generally recommend low-viscosity oil, but never change the grade arbitrarily. Always refer to the vehicle manual's recommended values. Choosing the wrong viscosity can lead to wasted fuel at best or engine damage at worst.
