What are the performance and specifications of lubricating oil?
3 Answers
Lubricating oil serves functions such as lubrication, cleaning, cooling, sealing, and friction reduction for the engine. In the domestic market, common lubricating oil specifications include eight types: 0W16, 0W20, 0W30, 5W20, 5W30, 5W40, 15W40, and 15W50. The lubricating oil specifications contain the letter W, which stands for winter. The number before W indicates the viscosity of the oil at low temperatures. The smaller the number, the better the cold resistance. The number after W represents the kinematic viscosity standard at 100 degrees Celsius. The larger the number, the better the high-temperature resistance index. Precautions: Automotive engine lubricating oils should not be mixed. Although they are all composed of base oils and additives, different types of lubricating oils have different base oil and additive compositions, resulting in varying performance characteristics. Mixing different brands of engine lubricating oils can cause adverse reactions due to the different chemical additive components. The mixed oil may become turbid, its quality may degrade, and its lubrication performance, cooling capability, and other properties may decline, shortening its service life.
I've worked in auto repair shops for over 20 years, and the quality of engine oil directly affects engine lifespan. Its primary functions are protecting internal components by reducing friction, cleaning carbon deposits, preventing rust, and resisting high-temperature oxidation. For oil grades, the most common is something like 5W-30. The numbers represent viscosity ratings - the smaller the number before W, the easier cold starts are in winter; the larger the number after W, the more stable it remains at high temperatures without thinning out. Synthetic oils generally perform better but cost more, while mineral oils are cheaper but require more frequent changes. Grades also include API ratings like SP, indicating advanced additive technology for superior cleaning and protection. Using the wrong grade can cause premature engine wear or increased fuel consumption. I've seen cases where using incorrect oil led to major repairs costing thousands. Always check your vehicle manual for the right oil specification before changing - don't penny-pinch only to lose pounds later.
As someone who tinkers with my old car every day, engine oil is like the lifeblood of the vehicle—I personally change it during every maintenance. Its core functions are reducing engine noise, improving fuel efficiency, and trapping debris. For specifications, I always check the SAE rating, such as 10W-40, which means decent low-temperature (10-grade) flowability and high-temperature (40-grade) resistance to evaporation, while also considering API classifications like SN or SP-grade synthetic oil. Additionally, synthetic oil lasts longer, making it ideal for long-distance driving, whereas mineral oil requires more frequent changes but saves money. Pro tips: Always check the manufacturer certifications on the packaging when buying oil—don’t switch randomly; I inspect the oil level weekly and top it up immediately if low. In areas with extreme temperature swings, opt for multi-grade oil to avoid issues.
