What's The W?

What oil is in your auto? Did you know The W in a multi viscosity oil stands for its ``winter'' viscosity. During colder temperature the oil gets less viscous because engines are ``tighter'' when the temperature drops. Viscosity is how easily a fluid will flow. The lower the number the easier it flows and ``thinner'' it is. The viscosity of an oil is measured by its resistance to flow. There are two numbers that define the viscosity of an oil. The first number ends with the letter 'W', which stands for Winter. This measurement is related to how an oil flows when it is cold, such as at engine start-up. The second number is defined by how an oil flows when at higher temperatures normal engine operating temperatures. The smaller the number, the better it will flow. So a 5W-30 will flow easier than a 10W-30 at start-up temperatures and a 10W-30 will flow easier than a 10W-40 at normal engine operating temperatures. This is important, as engine oils naturally thicken as they cool and thin as they are heated. Thin, low viscosity oils flow easier to protect engine parts at cold temperature. Thick, high viscosity oils are typically better at maintaining film strength to protect engines at high temperatures. You should use the car engine oil suggested by the engine manufacturer in your vehicle. Considering its incredible usability, it should come as no surprise that the 5w30 engine oil is used so commonly.