Proposed Laboratory Methods for Predicting the Low-Temperature Pumpability Properties of Crankcase Oils

The inability of certain crankcase oils to flow and lubricate an engine at low temperature and the lack of a suitable bench test to predict this characteristic are of current concern to engine builders and oil formulators.

Two critical areas of oil flow at very low temperatures have been recognized by SAE and ASTM subcommittees. These are: the ability of an oil to flow to the oil screen of an engine fast enough to prevent “air binding,” and its ability to be drawn through the oil screen and pump inlet tubing without causing “pump cavitation.” The interrelation between these two factors is discussed and some engine pumpability data are presented which illustrate how one of these factors may affect the other.

Descriptions of four new bench tests are presented along with data to show their ability to predict the low-temperature pumpability properties of crankcase oils.