A gear-type oil pump driven by the intermediate shaft draws oil through a strainer in the bottom of the oil pan and forces it through a spin-on replaceable filter and into the engine's oil passages. A pressure relief valve limits the pressure in the system, and a filter bypass valve assures lubrication even if the filter is plugged. Diesel engines and high performance gasoline engines feature an oil cooler attached to the filter housing through which engine coolant circulates to help moderate oil temperature. In addition to a warning system for low oil pressure, a more sensitive dynamic oil pressure warning system operates at elevated engine rpm.