How to Distinguish Engine Oil Grades?
4 Answers
The method to distinguish engine oil grades is by looking at the viscosity index. The functions of engine oil are: 1. To alleviate friction and high temperatures; 2. To cool and reduce temperature; 3. To clean and purify; 4. To cushion and absorb shocks; 5. To prevent rust and corrosion. Engine oil, also known as engine lubricant, includes: 1. Base oil: The main component of lubricating oil, which determines the basic properties of the lubricant; 2. Additives: These can compensate for and improve the deficiencies in the performance of the base oil. The effects of using inferior quality engine oil are: 1. It degrades the quality of the oil, reducing its performance; 2. It damages the lubrication of precision parts like the fuel pump and injector; 3. It decreases the power output of the generator set; 4. It affects the combustion efficiency of the engine.
When you want to understand motor oil grade classifications, I usually start with abbreviations like SAE and API. SAE refers to the number combinations before and after the 'W', such as 5W-30. The 'W' stands for winter temperature adaptability, the '5' indicates good low-temperature flow performance, and '30' represents high-temperature protection viscosity—the lower the number, the smoother cold starts will be. API ratings like SN or SP denote engine performance standards, with newer letters indicating more advanced oil protection that meets modern engine requirements. Always check your vehicle's manual or consult a professional technician when selecting oil to avoid engine wear from using the wrong type. In northern winters, I prefer low W-value oils like 0W-20, switching to slightly higher grades in summer. This knowledge may seem minor, but it can significantly extend your car's lifespan.
The differences in oil grades mainly lie in viscosity and standards. In the SAE code like 10W-40, 10W represents cold-start viscosity, where a smaller number means better flow at sub-zero temperatures, preventing winter starting issues; 40 indicates high-temperature stability. API grades like SL or SM relate to cleanliness and anti-wear performance, with newer standards like SP being more efficient than older ones. I adjust based on seasons and driving habits - for instance, using higher viscosity for frequent highway driving. The key is not to skimp, as using the wrong grade can cause engine noise. Regular oil change checks are recommended.
For oil grades, SAE indicates viscosity. For example, in 0W-20, 0W is suitable for extreme cold, while 20 maintains thickness at high temperatures. API represents performance levels like SN, which is ideal for new cars and provides better protection. I always check the vehicle's manual to confirm the matching grade to avoid affecting fuel consumption or causing carbon deposits.
