TM-9-2320-285-24-2
TRUCK TRACTOR, YARD TYPE, 43,500 LB GVW, DED, 4X2, ARMY MODEL M878A1
TECHNICAL MANUAL; ORGANIZATIONAL, DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL
OCTOBER 1985
TM-9-2320-285-24-2 - Page 9 of 698
TM 9-2320-285-24-2
3-2.
ENGINE TROUBLESHOOTING
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
1.
ENGINE LACKS POWER
Perform stall test (para 3-17a(3)).
a. If maximum engine speed is excessive, troubleshoot transmission (para 3-14).
b. If maximum engine speed is low, refer to TM 9-2815-205-34 for troubleshooting of the engine and its
components.
3-3.
COOLING SYSTEM TROUBLESHOOTING
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
1.
ENGINE OVERHEATS OR DOES NOT REACH OPERATING TEMPERATURE
Step 1.
Shut down engine.
Relieve all air pressure in air system (para 2-41h(1)).
Try to rotate fan by hand.
a. If fan cannot be rotated by hand, repair fan clutch assembly (para 3-5c).
b. If fan can be rotated by hand, proceed to step 2 below.
Step 2.
Disconnect tubing from fitting at top of fan clutch assembly (para 2-15e).
Apply 90 to 120 psi air pressure to fitting.
Check if fan can be rotated by hand with air pressure applied to fitting.
a. If fan can be rotated by hand, repair fan clutch assembly (para 3-5c).
b. If fan cannot be rotated by hand, proceed to step 3 below.
Step 3. Check radiator and hoses for leakage or damage.
a. If radiator is leaking or damaged, replace (para 3-5a).
b. If hoses are leaking or damaged, replace (para 2-15c).
c. If leakage and damage are not observed, refer to TM 9-2815-205-34 for troubleshooting of the
engine cooling system.
3-3
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