TM 10-3930-671-24 e) Check    engine    oil    to    see    if    it    contains coolant. f) Check that radiator cap has correct pressure rating.  Replace if incorrect. g) Pressure  test  the  radiator  cap.    Replace  if faulty. h) Pressure    test    the    radiator    and    cooling system.  Repair any leaks or blockage. i) Test   the   engine   thermostat.      Replace   as needed. Cooling System Inspection WARNING Use  extreme  care  when  removing  the cap from the radiator.  It is good safety practice  to  use  a  shop  cloth  to  cover the    radiator    cap    while    it    is    being removed.    Wrap  the  cloth  around  the cap   and   turn   cap   slowly   to   the   first stop.    Step  back  while  the  pressure  is released  from  the  system.    When  you are  sure  all  of  the  pressure  has  been released,  press  down  on  the  cap  with the cloth in place, turn, and remove the cap.          Stand     clear     of     the     radiator opening;  hot  coolant  may  splash  out. Failure    to    follow    these    instructions could  result  in  serious  personal  injury from    hot    coolant    or    steam    blowout and/or damage to the cooling system or engine. NOTE A     coolant     solution     containing     50% ethylene glycol provides freezing protection to -34°F (-37°C). 1. Remove the radiator cap. 2. Inspect  the  condition  of  the  coolant.    Look  for excessive  contamination,  rust,  or  oiliness,  and gummy  deposits  in   the   coolant   solution.      The coolant should have a clean appearance. 3. Check the PM time Interval, or the condition of the    coolant,    to    determine    if    it    needs    to    be changed (drained and replaced). 4. Inspect   the   radiator   cap.      Check   condition   of upper   and   lower   rubber   seals   (with   overflow reservoir,  cap  has  two  seals).    Check  the  seal holder   and   spring   for   correct   movement   and operation.  The rubber seal face should be clean and not damaged.  Look for nicks and cracks in the seals.  Replace the cap if it is defective. 5. Be    sure    the    radiator    cap    has    the    correct pressure   rating.      System   Pressure    (Radiator Cap) 14 psi, nominal. Refer   to   Section   2.1,   Service   Specifications,   Cooling System. 6. Inspect the radiator cap sealing surfaces located in  the  radiator  filler  neck.    Look  for  nicks,  deep scratches, or damage which may cause radiator cap leakage. 7. Inspect the overflow pipe and tubing for clogging damage   and   wear.      Clean   the   overflow   pipe. Remove    any    contaminants    that    can    cause restriction.  Replace the tubing if it is faulty. 8. Inspect   and   clean   the   overflow   reservoir,   as needed. F-95