TM 5-2420-230-24-2
roubleshooting Symptoms Charts
B3.9 and B5.9 Series Engines
Page TS-20
Section TS - Troubleshooting Symptoms
Coolant Temperature is Above Normal Sudden Overheat
This is symptom tree T023.
Cause
Correction
Inspect the engine and cooling system for
Coolant level is below specification
.......
external coolant leaks. Repair if necessary.
Add coolant. Refer to Procedure 008-018.
OK
F
an drive belt is loose, tight, or not in align-
Check the fan drive belt. Refer to Procedure
.......
ment
008-002.
OK
T
Check or replace the temperature gauge. Refer
emperature gauge malfunction
.......
to the OEM service manual.
OK
A
Check and repair fan shroud, shuttters,
irflow to the radiator is restricted (nonmarine
.......
shutterstat, sensor, fan clutch, and viscous fan
engines only)
as required. Refer to the OEM sevice manual.
OK
C
ooling system hose is collapsed, restricted, or
Inspect the radiator hoses. Refer to Procedure
.......
008-045.
leaking
OK
T
Check the thermostat for the correct part
number and for correct operation. Refer to
hermostat is not correct or is malfunctioning
.......
Procedure 008-013.
OK
W
Check the water pump for correct operation.
Replace the water pump if necessary. Refer to
ater pump is malfunctioning
.......
Procedure 008-062.
OK
F
Check the vent lines and the fill line for correct
ill line or vent lines are restricted, obstructed,
.......
routing and for restriction. Refer to OEM
or not routed correctly
specifications.
OK
A
ir or combustion gases are entering the
Check for air or combustion gases in the
.......
cooling system
cooling system. Refer to Procedure 008-019.
OK
T
(Continued)
L-604
