LOW TEMPERATURE BEHAVIOR OF MOTOR OILS: A Study of the Dependence of Cranking Speed on Motor Oil Viscosity

ABSTRACT

The behavior of motor oils at low temperatures is obviously important to the performance of the motor. Low temperature cranking speeds have been shown to be dependent on the viscosity, and in a previous paper the author has shown that the viscosity characteristics of motor oils at these temperatures may be unusual, especially when they contain Viscosity Index Improvers.

In this paper the author has analyzed the results of 250 cranking tests conducted at temperatures from +3° to −35°F. These results were compared using the viscosities as determined in a moderate shear viscometer and as extrapolated and calculated by the ASTM chart and a recently published analytical technique.