What is the method for distinguishing automotive oil grades?
2 Answers
Automotive oil grades are distinguished as follows: 1. The 'S' series represents oil for gasoline engines; 2. The 'C' series represents oil for diesel engines; 3. If both 'S' and 'C' letters are present, it indicates that the oil is suitable for both gasoline and diesel engines. The functions of engine oil are: 1. To alleviate friction and high temperatures; 2. To cool and reduce temperature; 3. To clean and remove contaminants; 4. To dampen vibrations and cushion impacts; 5. To prevent rust and corrosion. Engine oil, also known as engine lubricant, can have the following impacts when using inferior quality oil: 1. It degrades the quality of the oil, reducing its performance; 2. It disrupts the lubrication of precision components such as fuel pumps and injectors; 3. It decreases the power output of the generator set; 4. It affects the combustion efficiency of the engine.
I always thought distinguishing between oil grades was pretty straightforward, mainly by looking at the labels on oil bottles. The label shows the SAE viscosity grade, like numbers such as 5W-30. The 'W' stands for winter, and the smaller the number before it, the easier it is to start the engine in cold weather. For example, 5W flows smoothly at temperatures as low as -30°C. The larger the number after the 'W,' the better the protection at high temperatures, so using 30 or 40 in summer is fine. There’s also the API grade, like SP or SN, which indicates the oil’s quality and environmental standards. Newer standards like SP are better suited for modern engines to reduce wear. Different cars and seasons require different grades—my old car uses 10W-40 in summer to prevent overheating and switches to 5W-30 in winter for easier starts. Remember not to buy randomly; the manual clearly states the recommended grade. Using the wrong one can lead to sludge or engine wear. I always check the label during each maintenance to confirm.
