is a system developed by the Society
of Automotive Engineers (SAE) to classify
engine oils by viscosity grades. Oils are
classified based on their measured viscosity at high temperature for
single grade oils and at low and high
temperatures for multi-grade oils.
Multi-grades have a high viscosity index
(V.I.) and therefore may fall into more than one SAE grade
classification, e.g., SAE 1OW-40, ("W" denotes suitability for winter, or
cold weather use). Maximum cranking viscosities and pumping temperatures are
defined in order to satisfy SAE low-temperature requirements.
Low-temperature viscosity is measured at a different temperature for each
grade. High shear viscosity is measured at 150°C under high-shear conditions
that duplicate those experienced in the ring zone of an operating engine.
Application
Notes:
