Diagnosing Lubricating System Malfunctions - Dodge D250 1990 Service Manual

Engine Lubricating System
Page 9B-6
Base Engine Components
DODGETurbo Diesel
o ° c
To Oil Pan
32 °F
CTT1
From Pump
To Oil Cooler
Diagnosing Lubricating System Malfunctions
Be sure to check items related to oil pressure, such as: gauges,
high and low oil level, excessive oil contamination, oil viscosity,
etc.
High Oil Pressure
High oil pressure usually occurs after the engine is first started
in cold weather. The lubrication system does not have a coid
start relief valve. The pressure regulating valve components are
machined to a size that will relieve the excessive pressure
created by cold engine oil.
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To Oil Cooler
From Pump
Oil Pressure Regulating Valve
The engine will have high oil pressure if the regulator sticks in
the closed position. Check the regulator for freedom of
movement.
Low Oil Pressure
Low oil pressure can be caused by several lubrication system
related malfunctions. To begin the Investigation, determine the
engine operating conditions when the low pressure was first
observed.
Oil Level
Low oil level can cause low oil pressure.
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Caution; Never operate t h e engine w i t h the o i l level
below the low (L) mark.