Rick's Free Auto Repair Advice

Posts Tagged: viscosity index

Viscosity Index

What is viscosity index? Viscosity index is a value that represents how much the viscosity (thickness/flow) of a lubricating fluid, motor oil, transmission fluid, power steering fluid or gear oil changes with temperatures between 40°C and 100°C (ASTM D2270 test routine). All lubricating oil thins as temperature increases. In other words, it thins out. As temperature decreases, viscosity increases. To combat thinning at higher temperatures, manufacturers add viscosity improvers.  So the total change in viscosity over a given temperature range is its viscosity index of VI. The higher the VI, … Read More


Custom Wordpress Website created by Wizzy Wig Web Design, Minneapolis MN