What is the difference between 0W20 and 0W40 engine oil?
2 Answers
OW20 and OW40 are viscosity grades of engine oil, where higher numbers indicate higher viscosity. The specific differences are as follows: 1. The base viscosity of 0W20 and 0W40 engine oils differs. 0W40 engine oil has a higher viscosity than 0W20, meaning that at the same temperature, 0W40 flows much less easily than 0W20. 2. The high-temperature shear resistance of OW20 and OW40 engine oils varies. 0W40 engine oil has higher shear resistance than 0W20, providing a stronger and thicker oil film. 0W-40 offers better high-temperature protection due to its higher kinematic viscosity.
When I first bought my car, I was really confused about choosing engine oil. The 0W20 oil is especially worry-free for cold starts. The '0' in 'W' indicates excellent winter performance, ensuring smooth ignition even at -35°C without freezing the engine. The '20' number represents low viscosity at high temperatures, lubricating the engine like flowing water with minimal friction, naturally reducing fuel consumption. For daily commutes with heavy traffic, it saves a lot on gas. On the other hand, 0W40 is different—the '40' means thicker viscosity at high temperatures, forming a tougher protective film, ideal for long-distance driving or heavy loads to prevent engine damage. But remember, modern engines with high precision often recommend 0W20 in the manual for fuel efficiency and environmental protection; older or performance cars suit 0W40 better for enhanced durability. Choosing the wrong viscosity might affect performance or cause wear. After driving for three years, I always stick to the manufacturer's recommendations for oil changes.
