Can 10w40 engine oil be used in winter?
3 Answers
10w40 engine oil can be used in winter, but it depends on the minimum winter temperature in the region where the vehicle is used. This can be understood by examining the specifications of 10W40 engine oil. Below is an expanded explanation: 1. Firstly, the number 10 represents the low-temperature startup performance indicator. The smaller the number, the better the low-temperature startup performance. A value of 10 indicates that the oil can ensure normal startup at -25°C. The "W" stands for "Winter," indicating that this oil is suitable for winter use. The number 40 represents the oil viscosity—the higher the number, the greater the viscosity, and the better the high-temperature performance and high-temperature shear resistance. Therefore, whether to use this type of oil depends on the minimum temperature in the region where the vehicle is located. 2. The American Petroleum Institute (API) has established a standard for labeling engine oils, typically using formats like 5W-30 or 0W-40. This labeling is divided into two parts: the part after the hyphen "-" represents the oil's high-temperature shear resistance at 100°C and also indicates the base viscosity of the oil. A higher number means greater shear resistance, thicker oil film, higher base viscosity, and poorer fluidity. Conversely, a lower number means lower shear resistance, thinner oil film, lower base viscosity, and better fluidity. The "W" before the hyphen stands for "Winter" and represents the oil's low-temperature fluidity, i.e., low-temperature startup performance. The smaller the number before the "W," the better the low-temperature fluidity and startup performance. Subtracting 35 from the number before the "W" gives the minimum startup temperature for that oil viscosity. For example, 5W indicates a minimum startup temperature of -30°C. From the above explanation, 40 has a higher base viscosity, while 30 has a lower base viscosity. The difference between 10W and 15W is that 10W has a minimum startup temperature of -25°C.
As someone who enjoys studying automotive technology, I want to discuss the use of 10w40 engine oil in winter. The 'W' in 10w40 stands for Winter, and the number 10 indicates the low-temperature viscosity – the lower this number, the better suited it is for cold weather. In regions where temperatures don't drop below -20°C, such as southern China or temperate zones, 10w40 can be used. However, in extremely cold areas like northern China where temperatures may reach -30°C, 10w40 makes the engine work harder during cold starts due to its higher viscosity and poorer fluidity, which can increase wear. The ideal winter oils are those starting with 5w or 0w, such as 5w30, as they provide smoother cold starts. I always emphasize checking the owner's manual to confirm the manufacturer's recommendations and then combining that with local temperature variations to decide on the appropriate oil. Regular oil changes and warming up the engine for a few minutes can also help protect it.
From my years of driving experience, using 10w40 oil in winter is usually fine, as long as the temperature isn't too extreme. Where I live, winter averages around -10°C, and starting the car with 10w40 is relatively smooth. However, I once tried starting it at -25°C, and it was a bit sluggish, requiring some extra effort. The key is to ensure the oil is fresh and not degraded, otherwise, its protective effect diminishes. I recommend fellow drivers adjust according to the actual weather; if it's too cold, switch to a thinner oil like 5w to reduce cold-start wear. Also, don't forget to keep the battery in good health, as winter puts a heavier load on it.
