What is the difference between 0w40 and 5w40?
2 Answers
0w40 and 5w40 differ in the following aspects: 1. Different references: 0w40 refers to fully synthetic oil; 5w40 refers to semi-synthetic oil. 2. Different definitions: 0w40 is a man-made engine oil that involves chemical decomposition of various natural substances during production; 5w40 is one type of automotive engine oil, with semi-synthetic oil being based on semi-synthetic base oil. More details are as follows: 1. Engine oil, also known as motor lubricant, serves to lubricate and reduce friction in the engine, assist in cooling, seal against leaks, prevent rust and corrosion, and provide shock absorption. 2. Engine oil consists of two parts: base oil and additives. The base oil is the main component of lubricating oil, determining its fundamental properties, while additives compensate for and improve the shortcomings of the base oil, imparting certain new characteristics.
I often drive in the frigid winter regions of the north and have noticed a significant difference between 0W-40 and 5W-40 engine oils in terms of cold-start performance. The 'W' in 0W-40 stands for Winter, and the '0' indicates that it flows more quickly in extremely cold weather—like at -30°C—allowing the engine to lubricate rapidly and reduce wear. The '5' in 5W-40 means it’s more suitable for slightly milder temperatures, such as around -20°C, but may lag a bit during ultra-cold starts. The '40' in both denotes the same viscosity at high temperatures, ensuring strong protection when driving at high speeds. I believe oil selection should consider local climate—if you frequently encounter heavy snow, 0W-40 improves cold starts, saves fuel, and runs quieter; in milder weather, 5W-40 is practical enough. Before each oil change, I check the weather forecast to ensure the oil matches the season, which extends engine life and minimizes headaches.
