Dodge D250 1990 - Lubricating Oil Pump; Lubricating System Flow; Pressure Regulating Valve

Engine Lubricating System
Page 9B-2
Base Engine Components
DODGE Turbo Diesel
Lubricating System Flow
The schematics on the next four pages illustrate the engine oil lubrication system. The arrows indicate the flow path
of the oil. The lubrication pump draws oil from the pan and forces it through the lubrication system. The pressure
regulation valve controls the oil pressure in the system. The filter bypass valve ensures a supply of oil in the event
the filter becomes plugged. The piston pins are lubricated by the splash from the piston cooling nozzles. The oil
pump idler gear bushing is pressure lubricated. The remainder of the front gear train is lubricated by oil carry-over
and splash.
Lubricating Oil Pump
The engine uses a gerotor type pump.
Pressure Regulating Valve
The pressure regulating valve (2) is designed to keep the oil pressure from exceeding 414 kPa [60 PSI]. When the oil
pressure from the pump is greater than 414 kPa [60 PSI], the valve opens uncovering the dump port so part of the
oil is routed to the oil pan. Because of manufacturing tolerances of the components and the oil passages, the oil
pressure can differ as much as 69 kPa [10 PSI] between engines.