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

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 of 43 or 45 h to a final test temperature of -20 or -25°C. The viscosity measurements are made at a shear stress of 525 Pa over a shear rate of 0.4 to 15 s^-1. This test method is suitable for measurement of viscosities ranging from 4000 mPas to >400 000 mPa·s, and is suitable for yield stress measurements of 7 Pa to >350 Pa.

1.2 This test method is applicable for used diesel oils. The applicability and precision to other used or unused engine oils or to petroleum products other than engine oils has not been determined.

1.3 This test method uses the millipascal second (mPas) 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.