What does 5w40 mean?
2 Answers
The meaning of "5W-40" is as follows: 1. The "W" stands for "winter," indicating it is for winter use. The number 5 before the "W" represents the viscosity at low temperatures. The smaller the number, the better the fluidity at low temperatures and the stronger the cold resistance. 2. The "40" refers to the viscosity at 100°C. The larger the number, the higher the viscosity and the stronger the high-temperature resistance. 3. The "W" indicates the temperature range for oil usage, ranging from 0W, 5W, 10W, 15W, 20W, to 25W, etc. The smaller the number, the better the low-temperature fluidity, allowing it to perform better under low-temperature conditions. 4. The "40" indicates the viscosity of the oil at 100°C, with grades including SAE20, 30, 40, 50, and 60. The larger the number, the higher the viscosity. 5W50 is commonly referred to as multi-grade oil, meaning this oil meets the 5W viscosity requirement at low temperatures and the 40-grade viscosity requirement at 100°C.
I've driven quite a few cars before and know a thing or two about engine oil. The numbers 5W40 simply represent the viscosity grade of the oil. The W stands for Winter, and the 5 indicates good fluidity during cold starts, maintaining flow at around -30°C, making winter engine starts smoother. The 40 refers to the viscosity at high temperatures, ensuring proper engine lubrication in summer heat and protecting internal components. I always choose this viscosity when changing oil because it offers good balance, suitable for both cold and hot weather, especially ideal for city driving or long-distance trips. Using the wrong viscosity, like a thinner 5W30 that doesn't provide enough protection at high temperatures, can lead to increased engine wear and higher fuel consumption. Regularly checking the oil condition is crucial to prolonging engine life and avoiding costly repairs.
