What is the difference between 5w30 and 10w40?
2 Answers
The difference between 5w30 and 10w40 lies in their normal flow temperatures: 5w30 can flow normally at -30 degrees Celsius, while 10w40 can flow normally at -25 degrees Celsius. The 'W' stands for winter, and the smaller the number before it, the better the oil flows at low temperatures, indicating a lower applicable minimum temperature. The number after the 'W' refers to the oil's viscosity at 100 degrees, with higher numbers representing higher viscosity. Engine oil serves to lubricate and reduce friction, assist in cooling, seal against leaks, prevent rust and corrosion, and provide shock absorption. Engine oil consists of base oil and additives; base oil is the main component of lubricating oil, determining its basic properties, while additives compensate for and improve any shortcomings in the base oil's performance, making them an integral part of the lubricating oil.
I often help friends with car maintenance and notice many people are confused about oil viscosity. The main difference between 5w30 and 10w40 lies in the numbers: the 'W' stands for winter, where 5W flows better than 10W, making cold starts smoother, especially in sub-zero temperatures. The numbers 30 and 40 indicate high-temperature viscosity—30 is thinner, while 40 is thicker. Simply put, 5w30 is better suited for new engines or cold seasons, offering slight fuel savings; 10w40 has higher viscosity, providing stronger protection, often used for older cars or in hot weather to prevent engine wear. Using the wrong oil can lead to hard starts or increased fuel consumption, so always check your car's manual and follow the manufacturer's recommendation rather than guessing. Regular oil changes are crucial for extending engine life.
