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TRUCK SERVICE MANUAL
TM 5-4210-230-14&P-1
COOLING SYSTEM
Fig.  2  Coolant System Reservoir Installation
Fig.  3  System Warming Up
Fig.      4:   As   the   cooling   system   approaches   normal
operating  temperature,  the  vacuum  valve  in  the  radiator  cap
closes, the cooling system pressure rises to pressure controlled
by the cap pressure valve setting and no further air or coolant'
escapes the cooling system.
Fig.      5:   In   the   event   the   cooling   system   becomes
overheated    to    the    extent    that    pressure    rises    above    the
established   setting   (controlled   by   the   pressure   valve   in   the
radiator   cap),   excess   coolant   will   be   expelled   through   the
radiator  overflow  into  the  reservoir.    Coolant  discharged  from
the  radiator  in  excess  of  the  reservoir  capacity  would  overflow
from the reservoir.  Under this circumstance the engine should
be shut down, allowed to cool and the cause of the overheating
corrected.
Fig.  6: After the initial cooling system fill
Fig.  4  Normal Operating Condition
Fig.  5  Overheated System
and   the   engine   and   cooling   system   have   been   operated   to
normal temperature and the engine is then shut off, the system
in cooling down will draw coolant from the reservoir to replace
air expelled from the system during the warm-up period.  As the
warm-up  and  cool-down  cycle  is  repeated  during  operation  of
the  vehicle,  air  accumulated  in  the  system  will  gradually  be
expelled until a maximum fill condition is reached in the cooling
system.    The  coolant  level  in  the  reservoir  will  rise  and  fall
between the "ADD" and "FULL" lines.
NOTE:  Any  make-up  coolant  is  to  be  added  to  the  reservoir,
since the radiator cap should not normally be removed.
CTS-2019P  Page 6
PRINTED IN UNITED STATES OF AMERICA
 
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