ARMY TM 9-2815-254-24 AIR FORCE TO 38G1-94-2 SECTION  II.  EQUIPMENT  DESCRIPTION  AND  DATA 1-7.   GENERAL. The diesel engine (FIGURE 1-1) is four cylinder, four cycle, fuel injected, naturally-aspirated, and liquid-cooled. The firing order is 1-3-4-2. The number one cylinder is toward the fan end of the engine. The serial number is found on  left  side  of  the  cylinder  body  at  number  one  cylinder  location.  Rotation  of  engine  is  counterclockwise  as  viewed from flywheel. NOTE All locations referenced herein are given facing the flywheel end (rear) of the engine. 1-8. DETAILED  DESCRIPTION. 1-8.1. Cooling System. The cooling system consists of a radiator, water pump, cooling fan, thermostat, and connecting hoses. The fan is mounted on shaft of water pump and both are belt driven from the crankshaft pulley. The thermo- stat  controls  engine  temperature  and  is  installed  in  the  top  of  engine.  The  function  of  the  cooling  system  is  to  main- tain a specific operating temperature of 180° to 203°F (82° to 95°C) for the engine. 1-8.2. Lubrication System. The lubrication system consists of the oil pan, a gerotor type oil pump, spin-on type oil filter, and internal passages within the engine. There are two external oil lines, one for rocker arm lubrication and one for fuel injector pump lubrication. 1-8.3. Fuel System. The function of the fuel system is to inject a metered quantity of clean atomized fuel into the engine cylinders at a precise time near the end of the compression stroke of each piston. The fuel system consists of the  fuel  tank,  fuel  filter/water  separator,  fuel  injection  pump,  and  the  fuel  injectors.  The  fuel  tank  and  fuel  filter/wa- ter separator are not mounted on engine. The injection pump is mounted on the front cover and is driven by the timing  gears. 1-8.4. Electrical  System.  The  electrical  system  is  24  VDC  operation  and  consists  of  an  alternator,  starter,  externally mounted  batter  and  other  items  as  required.  The  alternator  is  mounted  on  front  of  engine  and  is  belt  driven. When  the  engine  is  operating,  the  alternator  supplies  24  VDC  to  recharge  the  battery  and  maintain  it  at  a  full  state of charge. The starter is mounted on the flywheel housing and when energized engages the ring gear of the fly- wheel to rotate the engine. 1-3