Can the engine oil changed in winter be used in summer?
2 Answers
Winter engine oil cannot be used in summer because winter oil has lower viscosity. Using it in summer would make the oil too thin, making it difficult to form an oil film, which would increase engine wear, shorten engine lifespan, and lead to higher fuel consumption. Therefore, it is best to change the oil according to the season or use all-season oil to better protect the engine. Winter oil grades are: 0W, 5W, 10W, 15W, 20W, 25W. The letter "W" stands for winter, and the smaller the number before "W," the lower the low-temperature viscosity, the better the low-temperature fluidity, and the lower the applicable minimum temperature. Summer oil grades are: 20, 30, 40, 50. The larger the number, the higher the viscosity and the higher the applicable maximum temperature.
Whether the oil changed in winter can continue to be used in summer depends mainly on whether the oil viscosity grade is suitable. In the SAE standard, the numbers on oil, such as 5W-30, indicate winter fluidity (W) and summer viscosity (30). If multi-grade oil like 5W-30 or 10W-40 was used in winter, it is designed to adapt to a wide temperature range and will perform well in summer heat, providing adequate engine lubrication. However, if ultra-low viscosity oil like 0W-20 is used in extremely hot regions, the oil may become too thin in summer, increasing engine friction and the risk of damage. I recommend checking the oil label for its grade and consulting the vehicle owner’s manual for recommendations. Don’t forget to consider the oil’s lifespan; if it was recently changed and hasn’t been driven much, it might be fine to keep using it. But during high-temperature seasons, especially for long-distance driving or if the oil turns black, it’s best to replace it to avoid risks. Regular maintenance is key—don’t just focus on seasonal changes.
