TM 10-3930-653-14&P 4-4-3.  COOLING SYSTEM 4-4-3-1.  DESCRIPTION The  cooling  system  is  of  the  conventional  pressure type.    A  centrifugal  pump  installed  in  front  of  the  timing chain cover serves to circulate the coolant The pressure type radiator filler cap  installed  on  the radiator   operates   the   cooling   system   at   higher   than atmospheric pressure. This  higher  pressure  raises  the  boiling  point  of  the coolant    and    increases    the    cooling    efficiency    of    the radiator. When   the   thermostat   is   closed,   the   coolant   only circulates    in    the    cylinder    head    and    block    for    swift warming   up   of   the   engine.      After   it   reaches   normal operating    temperature,  the  coolant  circulates  through the radiator also, to keep the engine at the thermostat’s rated opening temperature (1)  COOLANT LEVEL The  radiator  coolant  level  should  be  checked  and maintained below the bottom of the filler neck when the engine is cold. WARNING To    avoid    serious    personal    injury, never   remove   radiator   cap   quickly when  engine  is  hot.    Sudden  release of   cooling   system   pressure   is   very dangerous.        If    it    is    necessary    to remove  radiator  cap  when  radiator  is hot, turn cap slowly counterclockwise   to   the   first   step. After    all    pressure    in    the    cooling system is released, turn cap past the stop and remove it. (2)  DRAINING AND FLUSHING COOLING SYSTEM To  drain  cooling  system,  remove  radiator  cap,  release drain cock at bottom  of  radiator  and  drain  plug  on  right side    of    cylinder    block.        After    coolant    is    drained completely,  close  drain  cock  and  plug  and  refill  system kith clean soft water. 4-4-3-2.  WATER PUMP The  water  pump  is  of  a  centrifugal  type,  which  is mounted  on  the  engine  front.    The  fan  and  pulley  are bolted at the pulley hub. (1)  REMOVAL (1)  Drain coolant into a clean container. (2)      Remove   upper   and   lower   radiator   shrouds   (If equipped). (3)  Remove fan blade. (4)  Loosen fan belt. (5)  Remove water pump assembly and gasket from cylinder block. (2)  INSTALLATION (1)    Be  sure  to  clean  gasket  surfaces  in  contact  with pump and cylinder block Always   use   new   gaskets   when   installing   pump assembly.  Be sure to tighten bolts securely. (2)  Fill cooling system and check for leaks at pump. (3)  Install fan blade, and tighten attaching bolts securely. Install belt and adjust for specified tension. (4)  Operate engine at fast Idle and recheck for leaks. (5)  Install fan shroud. (3)  ADJUSTMENT Fan belt should be properly adjusted at all times.  A tight  belt  causes  wear  of  alternator  and  water  pump bearings.    A  loose  belt  results  in  improper  operation  of cooling fan, water pump and alternator. Check for belt deflection between alternator and fan pulley by a force of 10 kg (22 lb). Fan belt deflection: 8 to 12 mm (0.31 to 0.47 in) If   adjustment   is   necessary,   loosen   bolt   holding alternator  adjusting  bar  to  alternator.    Move  alternator toward   or   away   from   engine   until   correct   tension   is obtained. 4-58