TM 5-6115-593-12 TO 35C2-3-463-1 Section XXVI.  MAINTENANCE OF ENGINE ASSEMBLY 4-66. GENERAL.      The   engine   provides   mechanical power  to  drive  generator.    The  diesel  engine  is  a  12- cylinder, V-type, turbocharged, aftercooled type, rated at 750   hp   at   1800   rpm.      The   engine   air   intake   system consists  of  a  precleaner  with  a  replaceable  filter.    The engine is equipped with monitoring and control devices, lube  oil  cooler,  and  an  independent  governing  system. See figure 4-40. 4-67. WATER PUMP BELT.  (See figure 4-41) NOTE All     generator     sets     with     engine     serial numbers 10605201 and higher are equipped with    a    new    style    water    pump.        Sets equipped   with   the   new   pump   require   no belt adjustments.  The following procedure applies to serial number 10605201. a. Adjustment.          (1)     Remove     screws     and lockwashers on front adjusting sheave. (2) Turn    engine    over    manually    to    roll belts    outward    on    pulley    as    pulley sheaves     are     turned     in     to     obtain desired belt tension.  The engine can be turned manually as follows: (a) Remove cotter pin from manual engine crank bolt. (b) Push   bolt   toward   generator   to engage gear. (c) Use a wrench to turn bolt. (3) Turn front and rear adjusting sheaves while securing hub in stationary position to obtain desired belt tension. (4) Lock front and rear adjusting sheaves in     position     with     lockwashers     and screws. (5) Check belt tension by applying pressure   of   the   index   finger   at   the center of the longest span of the belt. Deflection  should  be  approximately  1 inch (25 mm). b. Replacement.  (See figure 4-41.  ) (1) To replace water pump belts, remove the    screws    and    lockwashers    which secure   the   adjusting   sheaves   to   the fixed sheave. (2) Loosen    the    adjusting    sheaves    and remove belts. NOTE Always  replace  belts  in  complete  sets  to prevent early failure and provide efficient operation.    Belt  riding  depth  should  not vary over 1/16 inch (1.59 mm) on new belt sets. (3) Belts    should    not    bottom    on    pulley grooves and should not protrude over 3/32   inch   (2.      4   mm)   above   top   of edge of groove. (4) Install     new     water     pump     belts     to pulleys and secure in position with the adjusting   sheaves,   lockwashers,   and screws. (5) Adjust the water pump belt tension as described in paragraph a, above. 4-68. SERVICING    DCA    WATER    FILTERS.        (See figure 4-40.  ) NOTE New  engines  are  shipped  with  a  DCA  pre- charge  element.    At  first  oil  change  (see Lubrication Order) replace pre-charge element  with  normal  DCA  Service  Element. Replace filter element at each oil change.  If coolant    is    drained    and    the    coolant    is replaced,  install  a  DCA  pre-charge  element and repeat cycle.  To test coolant corrosion inhibitor use Fleetguard DCA, Part Number 3300846-S,     or     Cummins     Coolant,     Part Number 3375 208, Test Kit.      4-99