Dodge D250 1990 - Lubrication for the Turbocharger; Oil Coolers; Oil Filter Bypass Valve; Oil Filters

Base Engine Components Engine Lubricating System
DODGE Turbo Diesel Page 9B-3
Lubrication for the Turbocharger
The turbocharger receives filtered, coded and pressurized lubricating oil through a supply line from the filter head. A
drain line connected to the bottom of the turbocharger housing returns the oil to the oil pan through a fitting in the
cylinder block.
Oil Coolers
The engines use full flow, plate type oil coolers (3). The oil flows through a cast passage in the cooler cover and
through the element where it is cooled by engine coolant flowing past the plates of the element.
Oil Filters
After the oil is cooled, it flows through the full flow oil filter. From the filter oil flows to the turbocharger and engine.
Oil Filter Bypass Valve
The oil cooler cover contains a bypass valve (5) that will let the oil flow bypass a plugged filter. The valve is designed
to open when the pressure drop across the filter is more than 138 kPa [20 PSI], as with a plugged filter, and lets the
oil continue on through the engine. When a filter becomes plugged, an oil pressure decrease of 60 kPa [10 PSI] or
less from the normal operating pressure can be observed on the vehicle oil pressure gauge.