What does 0w40 engine oil mean?
3 Answers
0W40 is the SAE standard viscosity value of engine oil, where 0W indicates that the oil can be used at a minimum temperature of minus 35 degrees Celsius, and 40 represents the kinematic viscosity standard at 100 degrees Celsius. Engine oil, also known as engine lubricant, serves to lubricate and reduce friction, assist in cooling, seal against leaks, prevent rust and corrosion, and provide shock absorption for the engine. It is often referred to as the lifeblood of a car. Engine oil consists of two parts: base oil and additives. The base oil is the main component of lubricating oil, determining its basic properties, while additives compensate for and improve the shortcomings of the base oil's performance, endowing it with certain new characteristics, making them an essential part of lubricating oil.
The numbers in 0W40 oil actually tell us how viscous the oil is at different temperatures. As a veteran driver with over a decade of experience, I find this quite important, especially during winter startups. The 0W indicates low viscosity in sub-zero temperatures, allowing the oil to flow quickly for smoother cold engine starts. The 40 means it maintains proper viscosity at high temperatures, like when the engine heats up in summer, providing lubrication and protection for components. I personally use this oil for long-distance travel vehicles, particularly in cold northern regions—it reduces startup difficulties and improves fuel efficiency. Remember, regular oil changes are crucial; don't wait until the oil turns black, or it could damage the engine. Just check your manual for the recommended viscosity when buying oil—using the right one truly extends engine life.
0W40 is one of the viscosity grades of engine oil. Having repaired cars for over a decade, I've encountered various issues. Simply put, the first number 0W indicates low viscosity in winter, making it suitable for cold regions to facilitate engine startup; the latter number 40 represents higher viscosity at high temperatures, protecting components from wear. In daily use, this oil is suitable for modern cars, especially those with turbochargers, as it maintains stable performance under various engine conditions. From experience, choosing the wrong oil—such as one that's too thin at high temperatures—may lead to oil burning, while one that's too thick increases fuel consumption. I recommend car owners select oil based on their local weather and vehicle type, and not extend oil change intervals too long—typically around five to six thousand kilometers is appropriate. Paying attention to oil brands is also crucial, as major brands tend to offer more reliable quality.
