What Do Motor Oil Specifications Represent?
4 Answers
Motor oil specifications consist of two parts: classification and viscosity rating. The oil label typically indicates viscosity and quality. Specifically, the viscosity of lubricating oil is marked with grades such as SAE, which stands for the Society of Automotive Engineers in the United States. The 'W' stands for winter. The smaller the number before 'W', the better the oil's low-temperature fluidity, the lower the usable environmental temperature, and the better the engine protection during cold starts. The number after 'W' (following the horizontal line) indicates the oil's high-temperature resistance. The larger this number, the better the oil's protective performance at high temperatures. The label after the oil classification specifies its viscosity rating. For example, in '15W-40, 5W-40', 'W' stands for winter. The smaller the preceding number, the better the oil's low-temperature fluidity, the lower the usable environmental temperature, and the better the engine protection during cold starts.
The oil model is essentially the specification identifier for motor oil, which I like to think of as the lubricating passport for a car. Those alphanumeric combinations, such as the common 5W-30, tell me about the oil's viscosity performance: the first number, 5, indicates its flow capability at low temperatures, the W stands for Winter, and the smaller the number, the better it is for cold starts; the second number, 30, shows the viscosity at high temperatures, with higher numbers offering better engine protection in scorching heat. Having driven many cars, I've experienced the struggle of using oil that's too thick in winter, resulting in difficult starts and higher fuel consumption. The model also includes performance grades, like API SN, which indicate cleaning and anti-wear standards—higher grades ensure a more durable engine. Although synthetic oil is more expensive, its longevity is superior, and I make it a habit to check it every 8,000 kilometers to prevent premature engine aging.
As an average family driver, I gradually understood the meaning of motor oil grades, which are crucial for driving safety. Simply put, a grade like 0W-20 indicates the oil's characteristics: the first part, 0W, means strong fluidity at low temperatures for easy engine starts; the latter number, 20, shows it maintains proper thickness at high temperatures to prevent engine overheating and wear. These numbers directly affect fuel consumption and noise levels—I noticed smoother driving after switching to the correct grade. Performance ratings like ACEA C3 are designed for specific vehicles to meet emission standards. Choosing the wrong grade can be problematic—a friend once used 5W-40 in a compact car, causing a sharp rise in fuel consumption. I recommend regularly checking the owner's manual and changing oil on schedule to protect the engine.
When I first started driving, I was completely clueless about oil grades, but later I learned that they represent viscosity characteristics. For example, 10W-40: the "10" indicates the low-temperature flow index, "W" stands for winter, and "40" is the high-temperature viscosity value. This combination ensures the oil remains thin and flows easily in cold weather while staying thick enough to protect the engine in hot conditions. Using the wrong grade in my first car caused slow starts, but after consulting a mechanic, I understood the importance of matching the right type. Performance ratings like API SP improve cleanliness and extend engine life. Choosing the correct grade saves both hassle and money.
