Understanding Oil Viscosity: What the Numbers Mean > 자유게시판

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When you look at a bottle of motor oil, اتوسرویس داوود you might see numbers like 5W-30 printed on the label. These numbers might seem confusing at first, but they are actually a clear way to describe how the oil moves at different temperatures. This property is called fluid resistance, and it’s one of the key factors in choosing the correct oil for your engine.

Viscosity refers to how thick or runny a fluid is. Think of honey versus water. Honey is thick and flows slowly—that’s elevated thickness. Water is thin and flows easily—that’s low viscosity. Engine oil needs to be thick enough to protect engine parts from friction and wear, but fluid enough for instant lubrication when the engine starts, especially in cold weather.

The numbers on the oil bottle are a dual system. The first number, followed by the letter w, stands for freezing conditions. This tells you how well the oil retains mobility at sub-zero environments. For example, in 10W-40, the 0 means the oil flows well in freezing temperatures. A smaller value like 5W means the oil is easier to pump in winter, which helps the engine start more easily in winter. A higher number like 15W means the oil is less mobile at low temps and may not flow as quickly in sub-zero climates.

The second number, after the w, tells you how viscous the oil is at 100°C, which is about 212 degrees Fahrenheit. In 10W-40, the 30 means the oil has a moderate thickness when hot. Greater values like 40 mean the oil maintains viscosity when the engine is running hot, which can be more effective for performance cars that operate under intense heat.

The w in the middle stands for low-temp rating, and it’s there to show that the oil has been tested for performance in dual climate environments. Modern oils are called multi-grade oils because they can function optimally across a extensive climate zones. They contain special additives that help them resist thinning under heat.

Choosing the ideal thickness matters. If you use oil that’s too thick when cold, your engine may face increased friction on ignition, leading to excessive friction. If you use oil that’s too light for high temps, it might fail to maintain film strength under heavy load. Always check your vehicle’s owner’s manual for the manufacturer’s recommended viscosity. Using the correct viscosity helps your engine function reliably, improve durability, and can even enhance economy.

In summary, the numbers on your oil bottle are a indicator to how the oil functions in cold and hot environments. The cold rating before the w tells you about start-up efficiency, and the second number after the w tells you about operating viscosity. Understanding these numbers helps you make a better choice for your car’s longevity.