What does 15w-40 mean for engine oil?
2 Answers
Engine oil 15w-40 refers to the viscosity of the oil, indicating its applicable temperature range from -20 degrees Celsius to 40 degrees Celsius. Below is a detailed explanation of the meaning of 15w-40 engine oil: 1. The meaning of 'w': 'w' stands for winter-grade oil; the smaller the number before 'w', the lower the ambient temperature it can be used in. 2. The meaning of the number after 'w': The number after the hyphen represents the ambient temperature for non-winter use, with a higher number indicating a higher applicable ambient temperature. Extension: Engine oil, also known as motor lubricant, serves to lubricate and reduce friction, assist in cooling, seal against leaks, prevent rust and corrosion, and provide shock absorption for the engine. Engine oil consists of two parts: base oil and additives. The base oil is the main component of the lubricant, determining its basic properties, while additives compensate for and improve the shortcomings of the base oil, giving it new performance characteristics.
The 15W in the 15w-40 oil marking indicates good fluidity at low temperatures in winter. The number 15 means it's not too thick at startup, making it easier to crank the engine. The 40 at the back indicates moderate viscosity at high temperatures, protecting parts from wear. I often use this oil in my four-door sedan, especially in places with significant seasonal changes like Beijing or Shanghai. It won't freeze up in winter and remains stable when climbing hills in summer. Many people ask why I choose this – I tell them it's like a universal solution, saving the hassle and cost of switching oils back and forth. Plus, the right viscosity can improve fuel efficiency and reduce consumption a bit. I recommend checking the oil level every 5,000 kilometers to prolong engine life – don't slack on this.
