TM 5-3805-262-20
3-7. COOLING SYSTEM TROUBLESHOOTING (CONT)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
1. ENGINE OVERHEATS (Cont).
Step 14. (Cont).
T e l l a s s i s t a n t t o s t a r t e n g i n e ; i f e n g i n e c a n n o t b e s t a r t e d , t e ll
assistant to crank engine for 30 seconds while you watch coolant in
water manifold for air bubbles.
a .
b .
If air bubbles rising in coolant in water manifold are seen, no-
tify direct support maintenance to replace cylinder head
g a s k e t ( s ) .
I f a i r b u b b l e s r i s i n g i n c o o l a n t a r e n o t s e e n , t e l l a s s i s t a n t to
shut off engine. Go to step 15 below.
Step 15. Test thermostats (page 4-89).
a . I f t h e r m o s t a t s t e s t o k a y , r e i n s t a l l t h e r m o s t a t s a n d t h e r m o s t at
housing (page 4-89).
Connect upper radiator hose to thermostat housing (page 4-75).
Fill radiator with coolant (page 4-71).
I n s t a l l a n d a d j u s t a l t e r n a t o r d r i v e b e l t s ( p a g e 5 - 5 ) .
Install engine left and right side panels (page 9-17).
Notify next higher maintenance level (engine must be checked
f u r t h e r ) .
b. If thermostats do not test okay, replace (page 4-89).
2. ENGINE DOES NOT REACH OPERATING TEMPERATURE.
Remove and test thermostats (page 4-87).
Replace thermostats (page 4-89).
3. COOLING SYSTEM NOT PRESSURIZED.
NOTE
With engine at normal operating temperature, run engine at high speed
for two minutes and return to idle speed. Carefully cover radiator cap
w i t h a c l o t h a n d r o t a t e c o u n t e r c l o c k w i s e t o f i r s t d e t e n t . A h i s s i n g
noise from cap and filler neck indicates that system is pressurized.
Step 1. Allow engine to cool and remove radiator cap. Rinse radiator cap
with clear water and install on cap adapter and pressure tester as
shown.
3-58
