A Laboratory Engine Test Study of Motor Oil Flow Properties in Winter Service

Laboratory engine low temperature pumpability test programs have been completed with two four cylinder gasoline engines. Both of these engines are reported to have been involved in low temperature field failures in recent years. Hardware and oil formulation effects have been studied and shown to have a significant impact on low temperature operability. Three commercially available viscosity modifiers are ranked for relative pumpability performance in each engine. In addition, evidence is given to explain the reasons for the field failures that occurred in these two engines.