Skip to main content

Viscosity Index

The measure of the rate of change of viscosity with temperature. Heating tends to make lubricants thinner; cooling makes them thicker. The higher the viscosity index is on a particular fluid, the less of a change in viscosity there will be over a given temperature range. In determining the viscosity index, two temperatures of viscosity are taken, one at 40°C and the other at 100°C.

Rate this answer
Rated1.2/5 (6 votes)