TM   10-3930-643-20 PRELIMINARY   PROCEDURES. 3 - 5 . Organizational   Preventive   Maintenance   Checks   and   Services   (PMCS). Organizational   Preventive   Maintenance   Checks   and   Services ITEM TO BE INSPECTED PROCEDURE: CHECK FOR AND HAVE REPAIRED, FILLED, OR ADJUSTED AS NEEDED PERFORM ALL OPERATOR PMCS FIRST Q-Quarterly A-Annually H-Hours I t e m    I n t e r v al No. Q      A      H Equipment Procedure 11 l FUEL  FILTERS Change   annually   or   when   loss   of engine   power   or   misfiring   is evident. 12 l COOLING  SYSTEM Check   coolant   condition   IAW TB  750-651. Drain,   clean   and refill   the   cooling   system   if required. Refer   to   paragraph 4-27. 3-11