What does the engine oil grade represent?
2 Answers
The engine oil grade represents the viscosity and quality of the oil. The viscosity of lubricating oil is often indicated using the SAE grade, where SAE is the abbreviation for the Society of Automotive Engineers. The 'W' stands for winter, and the smaller the number before it, the better the oil's low-temperature fluidity, indicating a lower usable environmental temperature and better engine protection during cold starts. The number after 'W' indicates the oil's high-temperature resistance; the larger the number, the better the oil's protective performance at high temperatures. The oil classification is represented by a combination of two letters. The 'S' series represents oil for gasoline engines, with general specifications ranging from SA to SN. Each subsequent letter indicates better performance than the previous one, with more additives to protect the engine. The further the letter is in the alphabet, the higher the quality grade.
I saw someone asking about the meaning of motor oil grades, so I’ll share my experience. A combination like 5W-30 actually describes the viscosity characteristics of the oil. The 5W represents the winter part—the smaller the number, the better the fluidity at low temperatures, making cold starts easier for the car. The 30 indicates the viscosity at high temperatures—a larger number provides better protection for engine components. Last time, I mistakenly used 10W-40, and it resulted in difficult starts in winter and some engine stuttering. Choosing the right grade is crucial—it affects fuel efficiency, engine wear, and overall lifespan. Always check your car’s user manual and stick to the recommended grade—don’t cheap out and experiment with different grades. During regular oil changes, check to ensure it matches the season. In summer’s high temperatures, you might need a higher viscosity grade to avoid overheating issues. Routine maintenance is simple—just consult a professional when in doubt.
