2. Faulty radiator caps. Radiator caps should
keep the cooling system pressurized to 14-17
PSI. If either one of yours is bad, replace it with
a new one FSN 2930-690-2701 (P/N
10866042). To discourage crew members from
stepping on and damaging the caps, paint a
"no step" caution on the deck nearby.


 A faulty cooling system or low coolant level is the next biggest cause of
overheating. Here's how the causes stack up.

 1. Improper Riling. Improper filling COOLING SYSTEM
causes air to be trapped in the system.
These air pockets become heat traps.
To prevent air pockets always...







 CHECK THESE
 CONNECTIONS
 FOR LEAKS





 S TRY UP-STREAM.
 WATER. HERE ~'
 VERY
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62


 Sn 4. Clogged radiators. Flush or clean internally
 Suspect the CO I clogged radiators like it's spelled out in TB
 thorouglY-lace ope- Ord 651 (Apr 64). This cleaning job is not. a
Shasis on the ahos routine job; it's used only to clean rusted or
1et hose, m iani0 ilet clogged cooling systems. The cleaning com-
 Lthe wate P oe pound used is FSN 6850-598-7328. A set of
e. Yee the bots a cleaning instructions come with the compound.
nections tight.
 I PUT THE
 POWDER IN ANP
 NOW I'M MIXIN'
 THE WHOLE I
 After a flush or cleaning job, always use Corro- WORKS.
 sion Inhibitor, FSN 6850-753-4967 (6-oz can). Use
 6 ounces for every 12 quarts of water. A 22-gal Don't pour
 cooling system takes about 7/2 cons. the inhibior
 into the
 Sia radiator in its
 powder form.
 Dissolve the
 stuff in hot
 or worm water
 then pour it into
 the cooling system.


 If your radiators are clogged externally, blow them out with hot water
and air under pressure; or have your support-steam them clean. To keep
external clogging to a minimum, don't let junk accumulate in the fan com-
partment. Vehicles in Southeast Asia should have their radiators removed and
cleaned at every Q-service when the power pack is our. Il


 5. Defective Thermostats. The only thing to do is
to replace them if you find yours are faulty.
Use FSN 6620-846-9848 to get new ones. Your
-20 TM shows how they're replaced.
 63


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