The entire engine lubrication system has been represented by a series-parallel network of flow passages and flow elements. The pressure distribution and flow rates in the network were computed according to pressure-flow characteristics of each element. The pressure-flow relationship for each network element was estimated using empirical pipe friction, expansion, and bend loss coefficients, as well as by using test rig results and a steady-state journal bearing model. The journal bearing model is basically that of the classical short bearing model with provision for heat transfer to the oil and the relative thermal growth of the journal and bearing system.When compared with diesel engine tests, the simulation predicted the pressure distribution throughout the engine and the flow rate through each branch within 10%. Although predicted bearing temperature rise data agreed well with steady-state bench test results, they were as much as 50% lower than temperature rise data measured on the engine.