What is the difference between 020 engine oil and 040 engine oil?
3 Answers
020 engine oil and 040 engine oil differ in viscosity: 020 engine oil has lower viscosity, while 040 engine oil has higher viscosity. 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 consists of two main components: base oil and additives. Base oils are categorized by quality into Group I, Group II, and Group III base oils, with Group I and II being mineral oils and Group III being synthetic base oils. The quantity and quality of additives directly affect the overall quality of the lubricating oil. Engine oils are classified into mineral oils, semi-synthetic oils, and full synthetic oils.
I've been driving my old car for over a decade and have tried various engine oils. The 020 oil, like 0W-20, is thin and flows smoothly, making cold starts in winter mornings particularly quick, with noticeably smoother engine rotation. As for 040 oil, such as 10W-40, it's thicker and more robust, offering better protection in high summer temperatures and preventing the engine from overheating too easily. The main difference lies in the numbers: 20 indicates lower viscosity at high temperatures, which saves fuel, while 40 means higher viscosity and better durability. Using 020 in my new car did reduce fuel consumption a bit, saving me a few dozen dollars on gas each month; 040 in my older car made the engine quieter but slightly heavier on the throttle. Always checking the manual for the recommended oil is the most reliable approach—don’t switch brands randomly to avoid damaging the car.
As a working commuter who frequently drives on highways, I've personally tried both 0W-20 and 0W-40 engine oils. The 0W-20, with its lower viscosity, offers quicker engine response, smoother acceleration in turns, and better fuel efficiency, making it cost-effective in city traffic jams. On the other hand, 0W-40, with higher viscosity, provides more stable power output but is slightly more fuel-consuming. The difference lies in the numbers: 20 is as thin as water, flows easily with less friction, while 40 is thick like honey, protecting against high-temperature wear. I find 0W-20 more economical as it allows me to travel a few extra kilometers per liter of fuel, whereas 0W-40 is only suitable for long-distance, high-temperature conditions and not recommended for frequent changes. Nowadays, many new cars recommend 0W-20 for its energy-saving and high-efficiency benefits.
