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 ,°,C and –,40 ,°,C. The precision is stated for test temperatures from –,40 ,°,C to –,15 ,°,C. The viscosity measurements are made at a shear stress of 525 ,Pa over a shear rate of 0.4 ,s^–,1 to 15 ,s^–,1. The viscosity as measured at this shear stress was found to produce the best correlation between the temperature at which the viscosity reached a critical value and borderline pumping failure temperature in engines.