What does 5w20 oil mean?

[LaLyla]

5w20 oil refers to the parameters of the engine oil. Here, the number 5 indicates the low-temperature fluidity of the oil—the smaller the number, the lower the ambient temperature it can be used in. Specifically, 5 represents the ability to withstand external temperatures as low as -30 degrees Celsius. The number 20 denotes the kinematic viscosity standard at 100 degrees Celsius, which is 20. This number serves as an indicator of the oil's high-temperature resistance—the higher the value, the better the oil's protective performance under high temperatures. Engine oil, also known as motor lubricant, is composed of base oil and additives. The functions of engine oil include: 1. Reducing friction and high temperatures; 2. Cooling and lowering temperatures; 3. Cleaning and purifying; 4. Damping and cushioning; 5. Preventing rust and corrosion.

[JoyLynn]

I often explain the 5w20 oil specification to my friends. The 'W' stands for Winter, and the number 5 indicates that the oil is thinner at low temperatures, making it easier to start the engine at around -25°C without causing wear due to overly thick oil. The 20 represents the high-temperature viscosity, meaning the oil maintains a moderate thickness at 100°C, ensuring sufficient protection for the engine during hot weather. This type of oil is multi-grade, suitable for all seasons, unlike single-grade oils which are only appropriate for one season. I recommend it because its good fluidity can improve fuel efficiency by about 1-3%, saving on fuel costs. However, it's crucial to check your car's owner manual, as not all vehicles are compatible. For instance, older models might perform better with 10w30. Choosing the right oil can more than double your engine's lifespan.

[Raymond]

5W20 belongs to the SAE viscosity standard. The 'W' number indicates the low-temperature flow index—a lower number like 5 means the oil forms a protective film quickly in cold weather, reducing startup resistance. The high-temperature number (20) refers to the oil's thickness at 100°C, preventing excessive thinning and wear under high heat. This design ensures uniform lubrication for the engine in both extreme cold and scorching heat, enhancing overall performance. I always recommend regularly checking the oil condition, as using the wrong viscosity—such as switching to 10W40—could increase fuel consumption by 5-10% and negatively impact emissions.

[JocelynLynn]

5W20 oil is simply the viscosity grade of the oil. The 5W part makes the oil slippery in cold weather for quick starts, while the 20 maintains protection in hot weather. After switching to this oil, I noticed my car runs quieter and smoother, and I even saved a bit on fuel costs. It's suitable for most modern cars, especially Japanese models or small-displacement engines.