Section  VI. LUBE OIL COOLER AND FILTER BYPASS VALVE 14-32.   General. The  lube  oil  cooler  is  mounted  on  the  right  side  of  the engine   cylinder   block   and   receives   coolant   from   the water   pump. Engine   lubricating   oil   is   pumped through   a   chamber   in   the   lube   oil   cooler.   The   cham- ber  walls  are  cooled  by  the  coolant  and,  in  turn, maintain  the  engine  lube  oil  at  a  safe  operating  tem- perature. 14-33.  Removal,  Disassembly,  and  Cleaning  of  Oil Cooler. a.  Removal.  Refer  to  the  Operator  and  Organiza- tional   Maintenance   Manual   for   removal   procedures. b.    Disassembly. See   figure   14-17   and   disassem- ble  the  lube  oil  cooler  as  shown. c.   Cleaning. Clean  all  metallic  park  with  clean- ing-solvent,   Federal   Specification   P-D-680. 14-34.   Inspection   and   Repair. a.   Inspection. (1)   Inspect   cooler   housing,   bonnet,   and   header for  cracks,  distortion,  and  scoring  of  mating  sur- faces. (2)   Inspect   cooler   assembly   passages   for   ob- structions. b.  Repair. (1)  Clean  passages  with  steam  under to   insure   that   there   are   no   obstructions. pressure (2)  Smooth  burrs  or  scoring  on  mating  surfaces with  a  fine  mill  file. (3)  Replace  any  parts  damaged  beyond  repair. (4)  Discard  all  gaskets  and  preformed  packing. 14-35.   Test,   Reassembly,   and   Installation. a.  Test. (1)  Make  up  two  plates,  one  with  a  drilled  and tapped   hole   to   accept   an   air   hose   fitting,   and   secure them  with  C  clamps  to  cover  the  oil  inlet  and  outlet openings  in  the  side  of  the  oil  cooler. Use   the   pre- formed  packing  to  seal  the  plates. (2)  Attach  an  air  hose  to  the  drilled  and  tapped plate;  submerge  the  oil  cooler  in  hot  water  until  the oil   cooler   temperature   is   up   to   approximately Test  for  leaks  with  air  pressure  of  100  psi. (3)  No  air  bubbles  shall  appear  at  either end  of  the  lube  oil  cooler. If  the  cooling  core 14-24 150°F. open is faulty,   the   oil   cooler   must   be   replaced.   If   the   shell is   damaged   it   must   be   replaced. b.  Reassembly. (1)  See  figure  14-17  and  reassemble  the  lube oil  cooler. (2)   After   reassembly,   place   the   lube   oil   cooler on   a   surface   plate   as   if   it   were   being   mounted.   Us- ing  a  feeler  gauge,  check  to  see  if  all  machined  sur- faces  contact  the  plate  within  0.  005  inch.  Loosen and   retighten   screws   to   obtain   this   clearance. c.  Installation.  Refer  to  the  Operator  and  Organ- izational    Maintenance    Manual. 14-36.  Lube  Oil  Filter  Bypass  Valve. a.   General. The  lube  oil  filter  bypass  valve  is  part  of  the  header block   of   the   engine   lube   oil   filter   assembly.   If   the filters   become   clogged,   such   that   the   differential pressure   across   the   combination   of   both   filters rises   to   45   psi   the   bypass   valve   opens   permitting unfiltered   oil   to   bypass   the   filters   and   go   directly to  the  main  oil  gallery. Cold  weather  induced  thickening  of  the  oil  will  cause the   filters   to   be   bypassed.   As   the   engine   oil   warms the   by-pass   valve   will   close   inserting   the   filter   ele- ments   into   the   oil   stream. b.   Removal. (See  figure  14-18) (1)   Both   oil   filters   must   be   removed.   Refer   to Operator   and   Organization   Maintenance   Manual. (2)  Remove  the  oil  filter  header  block  by  re- moving   six   cap   screws. (3)  Thoroughly  clean  the  area  at  the  rear  of  the header   block   where   the   bypass   valve   is   located. (4)   Remove   the   cap,   gasket,   spring,   piston sleeve   and   seat. c.   Cleaning   and   Inspection. Wash  valve  parts  in  cleaning  solvent.  Inspect  care- fully   for   wear   or   damage.   Replace   any   worn   or damaged   parts. d.    Installation. (1)  Install  valve bly. (2)  Renew  filter bypass   valve   gasket. in   reverse   order   of   disassem- header  gaskets  and  lube  oil