Can 15W-40 engine oil be used in summer?
2 Answers
15W-40 engine oil can be used in summer. Here are the specific details about 15W engine oil: 1. Engine oil with the specification 15W40 is suitable for all seasons. 2. Its applicable temperature range is from -15 degrees to 40 degrees. 3. It's important to note that the number following the W does not represent the upper temperature limit, but rather the kinematic viscosity standard at 100 degrees Celsius (between 12.5mm2/s and 16.3mm2/s). 4. W stands for winter, and 15 indicates the cold-start performance of the oil. The smaller the number, the better the oil's cold resistance. Especially in northern regions where winters are extremely cold, it's crucial to pay attention to the oil's cold resistance. If the oil is unsuitable for the local harsh environment, it will lose its intended effectiveness, and prolonged use can lead to severe engine wear.
I've been driving trucks for over a decade, and using 15W-40 oil in summer works perfectly fine. This oil performs exceptionally well under high temperatures, with the '40' indicating its high-temperature viscosity—it maintains sufficient thickness to protect engine components when temperatures rise. Last year during long-haul transport, climbing hills in 40-degree heat, the engine sound remained solid. I remember veteran mechanics teaching me years ago never to use overly thin oil in summer, as broken oil films can damage the engine. This viscosity suits older vehicles better, though newer models might require lower viscosity per manual. Still, 15W-40 works reliably for most regular cars in summer. Oil consumption increases slightly in extreme heat, so check the dipstick every 5,000 km—don't wait for the warning light to change it.
