What does 10W-40 engine oil mean?
2 Answers
Engine oil 10W40 refers to the viscosity grade of the oil being 10W40. The number before the 'W' represents the cold start performance; the smaller the number, the easier it is to start the engine in cold weather. Common grades include 0W, 5W, 10W, and 15W. Below are the methods for selecting engine oil and an introduction to oil grades: Methods for selecting engine oil: When choosing engine oil, it's not about selecting the most expensive one but rather about choosing the right oil based on the characteristics of your car's engine and your usual driving habits. You can categorize your choice by the oil used in winter and the oil used in summer. For winter, the primary consideration is the low-temperature viscosity grade. In summer, due to higher temperatures, there's no need to select an oil with a superior low-temperature viscosity grade. Engine oil grades: Engine oil grades are classified by quality and viscosity. Oils for gasoline engines are usually denoted by the letter 'S,' while oils for diesel engines are typically marked with the letter 'C.'
What does 10W-40 in engine oil mean? Let me share my driving experience. The W stands for winter, and the 10 represents the viscosity at low temperatures, such as during cold starts. It flows quickly, rapidly lubricating the engine and reducing wear. The 40 indicates the viscosity at high temperatures—when the engine is hot, it remains thicker to protect components from wear. Simply put, 10W-40 offers a wide range of coverage, making it suitable for both winter and summer. When choosing engine oil, always refer to your vehicle’s manual and avoid switching to a different grade arbitrarily. Using the wrong oil can make cold starts difficult in winter or lead to overheating and engine damage in summer. During maintenance, I check the oil level every 5,000 kilometers to ensure it adapts to seasonal temperature changes. Don’t skimp on this small expense—neglecting it could lead to premature engine failure and costly repairs. In short, matching your vehicle’s needs is what matters most.
