TM 10-3930-671-24 Section 7 - Preventive M aintenance In  order  to  obtain  maximum  efficiency  from  your  diesel engine, a definite maintenance program should be setup and  followed.    Haphazard  maintenance  will  only  lead  to faulty  engine  performance  and  shorten  engine  life.    All moving parts in the engine are subject to wear; however, wear    can   be   reduced    by    careful    operation    and    a planned maintenance program. In   general,   diesel   engine   operation   demands   careful attention   to   the   cleanliness   of   air,   fuel   and   oil   and maintaining coolant operating temperatures of 81°-93°C (180°-200°F.).  The following pages, covering Daily, 50, 250, 400 and 500 hour maintenance, have been worked out    with    our    field    service    division    as    "Minimum Requirements"   to   keep   your   engine   in   dependable operating condition. DAILY PREVENT AT IVE M AINT ENANCE SCHEDULE 1. OVERALL VISUAL INSPECTION OF ENGINE Look  for  evidence  of  fluid  leaks  on  floor,  cylinder  head and block, indicating loose fuel, oil or water connections- tighten If found. 2. CHECK OIL LEVEL OF ENGINE The  dipstick  indicates  the  high  and  low  oil  level  in  the crankcase-make   allowance   for   additional   oil   drainage back  into  oil  pan  if  engine  has  not  been  stopped  15 minutes.  The most efficient oil level is between the two dipstick levels. IMPORTANT:        Do    not    add    oil    until    oil     level approaches  the  low  mark-then  add  only  enough  to bring it to high level NEVER above.  Do not  operate the engine with oil below low level mark. 3. CHECK RADIATOR Fill radiator with a clean 50/50 water/anti-freeze mixture to   normal   level   maintained   due   to   expansion   when heated.    Visually  inspect  fan  and  belt  for  condition  and adjustment. 4. FILL FUEL TANK Fill   fuel   tank   at   end   of   day's   operation   to   prevent condensation forming in tank.  Clean filler cap and area around  spout  before  filling  to  prevent  entrance  of  dust into fuel system. 5. CHECK AIR CLEANER All engines, when operating, consume several thousand cubic  feet  of  air  per  hour.    Since  dusty  air  is  full  of abrasive matter, the engine will soon wear excessively if the air cleaner does not remove the dust before entering the cylinders.  On any air cleaner, operating environment dictates  the  air  cleaner  service  periods.    In  extremely dusty operations, this may be once or twice daily.  In dust protected areas the air cleaner should be serviced when changing  oil.    One  basic  type  of  air  cleaner  is  normally used-the dry replaceable element type. DRY-TYPE REPLACEABLE AIR FILTER Dry-type   air   filters   are   standard   equipment   on   many engines  and  it  is  most  important  that  the  dirt  buildup  in the  cartridge  does  not  reduce  the  air  flow  sufficient  to cause a noticeable loss in power.  They should normally be   serviced   every   50   hours   in   the   following   steps: (Extreme conditions will require daily cleaning).  Remove cover and cartridge after removing wing bolt do not allow dirt to fall into the exposed carburetor. CAUTION Do   not   damage   the   gasket   selling surface    or    bend    the    outer    screen portion of the cartridge while cleaning.    Replace  the  cartridge  If  in doubt Clean   cartridge   by   gently   tapping   flat   on   a   smooth horizontal surface to loosen and remove the heavier dirt deposits. F-163