ASTM D4684 : 02a

Standard Test Method for Determination of Yield Stress and Apparent Viscosity of Engine Oils at Low Temperature

Standard Details

1.1 This test method covers the measurement of the yield stress and viscosity of engine oils after cooling at controlled rates over a period exceeding 45 h to a final test temperature between -10 and -40°C. The viscosity measurements are made at a shear stress of 525 Pa over a shear rate of 0.4 to 15 s^-1.

1.2 This test method is applicable for unused oils, sometimes referred to as fresh oils, designed for both light duty and heavy duty engine applications. It also has been shown to be suitable for used diesel oils. The applicability to petroleum products other than engine oils has not been determined.

1.3 This test method uses the millipascal second (mPa·s) as the unit of viscosity. For information, the equivalent centipoise unit is shown in parentheses.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.