2-156 Change 1
KNOWN INFO
POSSIBLE PROBLEMS
DIAGNOSTIC FLOWCHART
TEST OPTIONS
REASON FOR QUESTION
KNOWN INFO
POSSIBLE PROBLEMS
TEST OPTIONS
REASON FOR QUESTION
NO
YES
NO
YES
ENGINE COOLING
IS THE COOLANT MIXTURE
CORRECT?
(SEE CHART ON PAGE 2-155.)
IS THE COOLANT AT THE
CORRECT LEVEL?
START
DRAIN &
REFILL COOLANT
FILL TO PROPER
LEVEL
1
2
NONE
COOLING COMPONENTS
ENGINE FAN BELTS
WATER PUMP AND
PULLEY
COOLANT MIXTURE TEST KIT
NSN 6630-00-169-1506.
The cooling system will not operate
properly if the mixture is incorrect.
Low coolant levels may cause
overheating.
COOLANT QUALITY OK
COOLANT LEVEL
COOLING COMPONENTS
ENGINE FAN BELTS
WATER PUMP AND
PULLEY
NO
YES
KNOWN INFO
POSSIBLE PROBLEMS
TEST OPTIONS
REASON FOR QUESTION
3
IS THE THERMOSTAT WORKING
PROPERLY?
REPLACE
THERMOSTAT
COOLANT OK
THERMOSTAT
GO TO 4,
Page 2-158
FEEL FOR COOLANT IN UPPER
RADIATOR HOSE WHEN ENGINE IS
HOT, OR REMOVE THERMOSTAT.
EXPOSE IT TO 190°F (88° C) AND
SEE IF IT OPENS.
COOLING COMPONENTS
ENGINE FAN BELTS
WATER PUMP AND
PULLEY
COOLANT TESTER
NSN 6630-00-105-1418.
An improperly functioning thermostat
can cause operating temperatures
that are either too hot or too cold.
VISUAL INSPECTION.
TM 9-2320-280-20-1
