It is the force of gravity that is at work here. The test oil is timed as to how long it takes to travel through a glass tube. (You may see it shown on specification sheets as mm2/s). It is named after an Irishman called Sir George Stokes from the 1840s. Kinematic viscosityis measured in Centistokes cSt. Kinematic viscosity– measures the normal operating temperature viscosity – it is measured at 100☌. Concept 2 – Kinematic viscosity is used to measure the second number – 30 in our example The first way is called Kinematic viscosity and the second way is called Dynamic viscosity. The oil chemists measure viscosity in two different ways. I know we don’t usually put honey in the microwave, but it works for this article. “You mean like honey taken out of the freezer compared to honey taken out of the microwave”. A delegate once said to me when I was doing automotive oil training. The other crucial point is that oil thickens up when it gets colder. Or put simply, is the liquid thick or thin? Take water and honey no misunderstanding here. Viscosity is the fluids resistance to flow. We need to have a better an understanding of what viscosity is, before moving on to defining how we measure it. The second number, the 30 is the viscosity at normal operating temperature. Most of us know this is the cold start rating.

High Temperature High Shear viscosity HTHSĬoncept 1 - What is viscosity and what does, for example, 0W-30 really mean? We are going to look at four key concepts relating to automotive oil viscosity.Ĥ. If you ask 10 people and there will be 10 different answers.

Welcome to the fascinating world of automotive oils.The odd thing about viscosity. We need to adopt the brace position or as Eddie Murphy said in “Beverly Hills Cop 2”.

High viscosity vs low viscosity