TM 10-3930-671-24 4.6. Engine Compression Pressure Test Diesel Engine Test Procedure ....................................................... F-83 Engine     Compression     Test     procedures     consist     of removing Injectors, installing a compression test pressure    gauge    to    the    cylinder    being    tested,    and cranking     the     engine     while     the     pressure     is     being measured. The information in this section describes general engine cylinder   compression   test   procedures   illustrated   with typical views of the subject activity. NOTE To  perform  this  service  procedure,  it  is  recommended that you first: • Park truck safely. • Apply parking brake. Block wheels. • Return  all  controls  to  NEUTRAL  and  turn key switch OFF, except as noted. Diesel Engine Typical Compression Test Procedure 1.    Be sure that crankcase oil is at the proper level. Bring engine up to normal operating temperature.  Stop the engine. 2.    Disconnect   the   fuel   shut-off   solenoid   so   the engine will not start. Escaping  fluid  under  pressure  can  have  sufficient  force to  penetrate  the  skin,  causing  personal  injury.  Before disconnecting  lines,  be  sure  to  relieve  all  pressure.  If Injured by escaping fluid, get medical attention at once. 3.    Remove  the  injector  and  seat  washer  from  the No.1 cylinder. F-83