What Do the Numbers in Motor Oil Represent?
4 Answers
The numbers in motor oil represent the following: Winter: Winter oil grades are: 0W, 5W, 10W, 15W, 20W, 25W. The symbol W stands for Winter, and the smaller the number before W, the lower the low-temperature viscosity, the better the low-temperature fluidity, and the lower the applicable minimum temperature. Summer: Summer oil grades are: 20, 30, 40, 50. The larger the number, the higher the viscosity and the higher the applicable maximum temperature. All-Season: All-season oil grades are: 5W/20, 5W/30, 5W/40, 5W/50, 10W/20, 10W/30, 10W/40, 10W/50, 15W/20, 15W/30, 15W/40, 15W/50, 20W/20, 20W/30, 20W/40, 20W/50. The smaller the number representing the winter part, and the larger the number representing the summer part, the higher the viscosity and the wider the applicable temperature range.
I encountered this issue when I first started driving. Seeing numbers like 10W-40 on the oil bottle really confused me. Later, I learned that those numbers represent the oil's viscosity. The number before the W, like 10, indicates the oil's flow capability at low temperatures—the smaller the number, the easier the car starts in cold weather, avoiding winter starting problems. The number after the W, like 40, means the oil is thicker at high temperatures, protecting the engine's internal components from wear. This directly affects the car's lifespan, so I always check the vehicle's manual when buying oil—choosing the right one saves money and ensures peace of mind. Otherwise, the engine can easily get damaged. I adjust the oil type seasonally—using a higher number in summer and a lower one in winter. Never skimp on quality—oil is the lifeblood of a car. Take care of it, and the car will run smoothly for a long time.
After buying a car, I often have to deal with engine oil matters. The numbers represent the oil's viscosity grade, simply put, like the thickness of coffee. For example, 5W-30: the 5 indicates the oil's flowability in cold weather—lower numbers mean it flows more easily below zero, protecting the engine for quick starts; the 30 means the oil is thicker at high temperatures, preventing friction between components during high-speed operation. Choosing the wrong oil can lead to increased fuel consumption or loud engine noises, so it's best to refer to the car manual. I've found that when changing oil, you also need to consider the climate—in northern winters, opt for 0W or 5W, and in summer, use 20 or 30. Regular maintenance is crucial. If the numbers aren't suitable, the car may feel sluggish or even shorten the engine's lifespan, which isn't worth the savings. Anyway, don't skimp on this—listening to a mechanic's advice is more reliable.
As a car enthusiast, I'm fascinated by oil viscosity numbers! They directly indicate the oil's thickness, like in 5W-20. The 5 represents the oil's fluidity during cold starts - a smaller number means the oil flows smoothly like water in cold weather. The 20 indicates high-temperature thickness - a larger number forms a robust protective layer at high RPMs, reducing wear. This is crucial for engine health - incorrect viscosity can break the oil film and accelerate component failure. I've seen some vehicle aging issues all stemming from mismatched oil. Always choose oil according to the manual when changing - don't experiment casually. After all, the engine is the heart - protect it well and the car can run smoothly for ten years.
