Can 15W40 engine oil be used in summer?

[McAllison]

15W40 engine oil can be used in summer and is classified as all-season oil, suitable for year-round use. Since engine oil has a certain freezing point and viscosity, which determines its applicable temperature range, 15W40 oil is more suitable for use in regions with temperatures above -20 degrees Celsius. The number before the W indicates the oil's low-temperature fluidity, or the minimum applicable temperature. A smaller number indicates better low-temperature fluidity and a lower minimum applicable temperature. The number 15 indicates a minimum applicable temperature of -20 degrees Celsius, with relatively average low-temperature fluidity. The number 40 represents the oil's viscosity value, indicating it is a high-viscosity oil with good high-temperature protection performance. Engine oil consists of base oil and additives. Base oil is the main component of lubricating oil, determining its fundamental properties, while additives compensate for and improve the shortcomings of the base oil, providing certain new properties, making them an important part of lubricating oil.

[SadieDella]

As a veteran driver who frequently takes long trips in high-temperature areas, I've been using 15w40 engine oil for many summers. This viscosity provides more stable oil film under 40°C high temperatures, making it particularly suitable for protecting older car engines. However, for new cars or Japanese vehicles, pay attention to the manual recommendations as they may use lower viscosity oils for better fuel efficiency. Also consider local temperatures - it works well with reduced engine noise in southern summers, but struggles in northern winters when low-temperature startup fluidity becomes poor, requiring a switch to 0w oil. The cleaning properties and anti-wear additives of the oil should also be from reputable brands, otherwise it's prone to deterioration under high heat. I always check the viscosity change of the old oil by touch before each oil change.

[DiLogan]

From the perspective of engine oil grade, 15w40 is perfectly suitable for summer use. The '15' before the W indicates a minimum winter operating temperature of approximately -20°C, which is irrelevant in summer; the '40' after the W represents the kinematic viscosity at 100°C, with higher values offering stronger high-temperature protection. When summer surface temperatures frequently soar to 60°C, a viscosity of 40 maintains oil film strength to prevent cylinder scuffing. However, two points should be noted: first, lower viscosity oils are more fuel-efficient in frequent stop-and-go traffic; second, some new vehicles equipped with GPFs are better suited for low-ash oils with C3 certification. Additionally, high-temperature volatility affects oil consumption, so opting for full synthetic oils from reputable brands is safer.

[Danielle]

15w40 is definitely suitable for summer use! This viscosity grade is specifically designed for hot weather conditions. During my time as a mechanic, I've seen many customers' vehicles experience insufficient oil pressure when using lower viscosity oil in summer. Especially for older vehicles or those frequently driven on mountain roads, 40 viscosity provides better stability under high temperatures. However, remember to pair it with a good oil filter - filtration efficiency is crucial in high-temperature conditions. Additionally, oil change intervals should be appropriately shortened during summer as high-temperature operating environments accelerate performance degradation. It's advisable to check around every 5,000 kilometers.

[VanSkylar]

Using 15w40 oil in summer is well-suited for older vehicles or high-mileage models. Last year, I helped a friend change to this oil for his 200,000-kilometer-old Buick Regal, and it ran flawlessly even in Hainan's 40-degree Celsius heat. The high-temperature viscosity of 40 provides better sealing when engine metal clearances increase, preventing oil burning. However, be cautious with newer turbocharged cars—switching from the recommended 0w20 to 40 viscosity might trigger a warning light. Driving habits also matter; for those who frequently redline, full synthetic oil is recommended. Regularly checking the dipstick is essential, as high temperatures accelerate evaporation and oil consumption.