TM-9-2320-272-23-1
TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)
TECHNICAL MANUAL; FIELD MAINTENANCE MANUAL; VOLUME 1 OF 5
SEPTEMBER 2012
TM-9-2320-272-23-1 - Page 377 of 1313
ENGINE OIL CONTAMINATED - Continued
STEP
3.
DO OIL COOLER OR AFTERCOOLER LEAK?
a.
Inspect oil cooler for leaks M939/A1 (Volume 2, WP
0233), M939A2 (Volume 2, WP
0229).
T0388DAA
Oil Cooler
Aftercooler
M939/A1
M939A2
Oil Cooler
Figure 3.
Engine Oil Cooler and Aftercooler.
b.
Inspect aftercooler for leaks.
NOTE
During engine operation, oil pressure will be higher than coolant pressure. A leak in oil
cooler will show oil in coolant. After engine is shut down, residual pressure in cooling
system will cause coolant to leak into oil.
c.
After engine has cooled off, check oil dipstick for evidence of coolant and surge tank for evidence of oil.
CONDITION/INDICATION
DO OIL COOLER OR AFTERCOOLER LEAK?
DECISION
YES - Oil cooler leaks. Replace oil cooler M939/A1 (Volume 2, WP
0233), M939A2 (Volume 2, WP
0229). Go
to Step (4) to verify problem is solved.
YES - Aftercooler leaks. Replace aftercooler (M939A2 only) (Volume 2, WP
0299). Go to Step (4) to verify
problem is solved.
NO - Replace engine M939/A1 (Volume 2, WP
0211), M939A2 (Volume 2, WP
0213). Go to Step (4) to verify
problem is solved.
TM 9-2320-272-23-1
0018
0018-4
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