Posts Tagged: engine oil viscosity

What Is Viscosity Index in Motor Oil?

Motor Oil Viscosity Index Explained: What It Is and Why It Matters for Your Engine Quick Summary • The viscosity index (VI) measures how much motor oil thickens in cold and thins in heat • A higher viscosity index oil maintains more stable protection across temperature changes • Modern engines rely heavily on high VI motor oil for fuel economy and wear protection • The traditional VI scale has flaws—it can underrate low-viscosity oils, which are common today Understanding motor oil viscosity index helps you choose the right oil—not just … Read More