ASTM D3829 Predicting the Borderline Pumping Temperature of Engine Oil
4. Summary of Test Method
4.1 An engine oil sample is cooled from 80 °C to the desired test temperature at a nonlinear programmed cooling rate over a 10 h period and held at the test temperature for the remainder of a 16 h period. After completion of the soak period, two standard torques of increasing severity are applied to the rotor shaft and the speed of rotation in each case is measured. From the results at three or more temperatures, the borderline pumping temperature is determined.
4.2 Alternatively, for some specification or classification purposes it may be sufficient to determine that the BPT is less than a certain specified temperature.
5. Significance and Use
5.1 Borderline pumping temperature is a measure of the lowest temperature at which an engine oil can be continuously and adequately supplied to the oil pump inlet of an automotive engine.
