What is the difference between 10w40 and 10w50 engine oil?
2 Answers
10w40 engine oil and 10w50 engine oil have the same low-temperature flow performance, but different viscosities, with 10w50 engine oil having higher viscosity. The following are details about engine oil: 1. The "w" in the engine oil model stands for "winter": If the engine oil model contains "w", it means the oil can be used normally in winter. 2. The number before "w" represents the low-temperature fluidity of the oil: 10w means the oil can flow normally at -25 degrees Celsius. 3. The number after "w" represents the high-temperature viscosity of the oil, with a larger number indicating higher viscosity: Generally, naturally aspirated engine vehicles can use 30 viscosity oil, turbocharged engine vehicles can use 40 viscosity oil, and high-performance, large-displacement engines require 50 or 60 viscosity oil. Therefore, when choosing engine oil, it is essential to select the appropriate oil based on the technical characteristics of the car engine, otherwise it may affect engine performance.
As a veteran driver with over a decade of experience, I've used both types of oil multiple times. 10w40 and 10w50 perform similarly in cold temperatures, both starting with 10w, meaning they can flow smoothly at temperatures below -20°C, ensuring no issues with cold weather starts. The main difference lies in the high-temperature numbers: 40 indicates the oil is thinner when the engine is hot, with better fluidity, making it more fuel-efficient and suitable for city commuting; 50 means the oil is thicker, providing better engine protection in hot weather or during aggressive driving, preventing component wear. I've noticed that using 50-grade oil makes the engine sound smoother when climbing mountain roads, but it slightly increases fuel consumption. I recommend checking your car's manual for the recommended oil type and not making arbitrary changes to avoid damaging the engine or wasting money. Regularly check the oil level during maintenance and stick to the same oil change intervals—it saves money and gives peace of mind.
