TM-9-2320-272-24-1
TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)
TECHNICAL MANUAL; UNIT, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE MANUAL; VOLUME 1 OF 4
JUNE 1998
TM-9-2320-272-24-1 - Page 115 of 1015
TM 9-2320-272-24-1
Table 2-1. Unit Preventive Maintenance Checks and Services (Contd).
ITEM TO
ITEM INTERVAL
CHECK/
NOT FULLY
PROCEDURE
MISSION
NO.
SERVICE
CAPABLE IF:
24
Semi-
Cooling
a.
Inspect coolant lines, hoses, and fittings for loose
annual
system
connections, cracks, frays, wear, and damage that could
cause leaks. Tighten loose connections. Replace any oil
line, hose, or fitting that is cracked, frayed, worn, or
damaged and could cause leaks.
b.
Inspect fan actuator and sensor for security of
mounting. Inspect air hoses and fittings for loose
connections, cracks, frays, wear, and damage that could
cause leaks. Tighten loose connections. Replace any air
line, hose, or fitting that is cracked, frayed, worn, or
damaged and could cause leaks.
c.
Inspect radiator core for clogged or bent fins, leaks,
and protruding debris, Clean clogged core and remove
debris (para. 2-15).
d.
On M939A2 series vehicles, inspect power steering
cooler core for clogged or bent fins, leaks, and protruding
debris. Clean clogged core and remove debris (para. 2-15).
e.
Inspect water pump vent/drain for obstructions.
f. Inspect water pump pulley and fan for play.
g.
Check drivebelt(s) for proper tension.
1.
For M939A2 series vehicles, check belt tensioner
for security of mounting 30 lb-ft (41 N•m) and condition
of fan drivebelt (para. 3-71).
2.
For M939/A1 series vehicles, check fan drivebelt
tension and adjust as required (para. 3-70).
3.
For M939/A1 series vehicles, check power steering
pump drivebelt tension (para. 3-230).
4.
For M939/A1 series vehicles, check water pump
drivebelt tension and adjust as required (para. 3-67).
5.
For M939/A1 series vehicles, check alternator
drivebelt tension (para. 3-78).
h.
Inspect fan blade for security, breaks, missing or loose
screws and rivets, and damage which could cause an
out-of-balance condition. For M939/A1 series vehicles,
refer to para. 3-72, and for M939A2 series vehicles, refer
to para. 3-64. Replace fan blade as required.
i.
Inspect surge tank, water manifold, thermostat
housing, radiator, engine oil cooler, transmission oil cooler,
and hoses for leaks, condition, and security of mounting(s).
j.
Inspect temperature sending unit for security of
mounting. Inspect sending unit wiring for frays, splits,
breaks, and worn or missing insulation.
k.
Check antifreeze protection temperature and adjust
if necessary to meet environmental conditions (para. 3-53).
2-27
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