Oil Filter; Oil Gauge; Oil Suction Tube; Bearings And Oil Pump - Dodge D250 1990 Service Manual

Bass Engine Components
DODGETurbo Diesel
Engine Lubricating System
Page 9B-7
Oil Filter
A plugged filter will cause a gradual loss of oil pressure by
approximately 69 kPa [10 PSI]. The pressure will return to
normal when the filter bypass valve opens:
Oil Gauge
Check the oil gauge and sending unit to make sure they are
operating correctly by verifying the pressure with a manual
gauge.
Oil Suction Tube
A loose suction tube, damaged gasket or crack in the suction
tube can cause a temporary loss of prime for the oil pump. The
engine will have low pressure or no oil pressure at starting
followed by normal oil pressure.
Bearings and Oil Pump
A steady decrease in oil pressure over a long period of time
can be an indication of worn bearings or excessive oil pump
wear.