Can 5W20 engine oil be used in summer?
2 Answers
It is not recommended to use 5W20 engine oil in summer. The definition of viscosity grade and the characteristics of 5W20 engine oil are as follows: Definition of viscosity grade: "W" stands for winter, and the smaller the number in front of it, the better the low-temperature fluidity of the engine oil. Characteristics of 5W20 engine oil: The number 5 represents resistance to external low temperatures of -30 degrees Celsius, W stands for winter, and 20 indicates that the kinematic viscosity of the engine oil at 100 degrees is 20. It has excellent low-temperature fluidity, relatively low operating resistance at low temperatures, and makes it easier to start the car. It is suitable for some small-displacement naturally aspirated engines that do not require high maximum RPM.
Using 5W20 oil in summer is generally fine, but it depends on your vehicle's specific conditions and local climate. From my experience, 5W20 means it flows well at low temperatures (like in winter) and has slightly lower viscosity at high temperatures (the '20' part), so in hot summer weather, the oil may thin out a bit, potentially reducing engine protection. I recommend checking your vehicle's manual first, as different models have different designs—some specifically recommend 5W20 for year-round use. In hot regions like Guangdong, if you mostly drive short distances or gently, 5W20 should suffice. However, if you frequently drive at high speeds or park under prolonged sun exposure, consider switching to a higher viscosity oil like 10W30 for added peace of mind to prevent oil pressure drops and increased engine wear. Regularly check your oil condition, especially in summer—monitor the dipstick and color changes frequently to avoid bigger issues down the road.
