How to Interpret Engine Oil Viscosity Codes: Your Complete Guide > 일반게시판

When you look at a bottle of motor oil, you might see numbers like 5W-20 printed on the label. These numbers might seem confusing at first, but they are actually a clear way to describe how the oil flows at multiple temperatures. This property is called flow characteristics, and it’s one of the most important factors in choosing the correct oil for your engine.

Viscosity refers to how thick or runny a fluid is. Think of maple syrup compared to tap water. Honey is dense and sluggish—that’s high viscosity. Water is light and mobile—that’s minimal resistance. Engine oil needs to be thick enough to protect engine parts from metal-on-metal contact, but fluid enough for instant lubrication when the engine starts, especially in low-temperature environments.

The numbers on the oil bottle are a two-tiered system. The initial number, followed by the letter w, stands for freezing conditions. This tells you how well the oil retains mobility at winter climates. For example, in 5W-30, the 5 means the oil performs efficiently in freezing temperatures. A lower number like 5W means the oil is more fluid at low temps, which helps the engine crank faster in winter. A larger value like 20W means the oil is less mobile at low temps and may lag in cold starts in icy conditions.

The second number, after the W, tells you how resistant the oil is at normal engine operating temperature, which is about 100 degrees Celsius. In 5W-20, the 30 means the oil has a medium thickness when at peak temperature. Heavier grades like 40 mean the oil maintains viscosity when the engine is at high RPMs, which can be ideal for performance cars that operate under intense heat.

The w in the middle stands for frigid conditions, and it’s there to show that the oil has been certified for performance in extreme temperature ranges. Modern oils are called multi-viscosity oils because they can perform well across a broad thermal spectrum. They contain polymer-based agents that help them resist thinning under heat.

Choosing the right viscosity matters. If you use oil that’s inadequately fluid in chill, your engine may not get enough lubrication, leading to accelerated component degradation. If you use oil that’s too light for high temps, it might not protect engine parts properly under performance driving. Always check your vehicle’s owner’s manual for اتوسرویس داوود the engine-specific rating. Using the optimal lubricant helps your engine operate efficiently, improve durability, and can even boost MPG.

In summary, the numbers on your oil bottle are a guide to how the oil performs in extreme climate scenarios. The preceding digit before the w tells you about start-up efficiency, and the post-W value after the w tells you about performance when the engine is hot. Understanding these numbers helps you make a optimal lubricant choice for your car’s health.