Is there a difference between 10w and 5w engine oil?
2 Answers
There is a difference between 10w and 5w engine oil, which lies in their low-temperature performance: 10w is suitable for an ambient temperature of -25 degrees Celsius, while 5w is suitable for -30 degrees Celsius. The number before the 'w' represents the oil's low-temperature fluidity, with a smaller number indicating better fluidity in cold conditions. The number after the 'w' represents the oil's high-temperature resistance, with a larger number indicating better protective performance at high temperatures. The functions of engine oil include lubricating and reducing wear in the engine, assisting in cooling, sealing to prevent leaks, preventing rust and corrosion, and cushioning vibrations. The composition of engine oil consists of: 1. Base oil: the main component of lubricating oil, determining its basic properties; 2. Additives: these compensate for and improve any deficiencies in the base oil's performance.
I've been driving for twenty years, hauling freight up north, so I'm particularly sensitive to oil temperature adaptability. The numbers 5w and 10w actually represent low-temperature fluidity, which becomes especially noticeable in winter. 5w maintains flow at -30°C, providing quick lubrication during cold starts and reducing engine wear. 10w can only handle down to -25°C; any colder and it thickens, making that painful dry grinding sound when starting the engine in the morning. In places like Heilongjiang, you must use 5w or even 0w, otherwise your car won't start after sitting outside overnight. For southern cities where winter temperatures stay above freezing, 10w is more economical. Also, pay attention to the second number in the oil grade, like 5w-30—the 30 indicates high-temperature viscosity. Choosing oil depends on local minimum temperatures and your vehicle manual, with summer heat making the second number even more crucial.
