TM   9-2815-202-34 MALFUNCTION TEST OR INSPECTION CORRECTIVE  ACTION COOLING   SYSTEM 11. ENGINE  COOLANT  OPERATING  TEMPERATURE  ABOVE  NORMAL Step 1. Step 2. Step 3. Step  4. Step 5. Check coolant level. Check operation of vehicle cooling system (Refer to appropriate vehicle type-20 maintenance  manual). Check for collapsed, cracked, or disintegrated hoses. Check thermostats for operation. Remove thermostat and test (Refer to Para 4-8). Check for combustion gases in the cooling system. a.  Remove  radiator  filler  cap. WARNING Protective fan screens must be Installed prior to doing maintenance  In  the  engine  compartment  when  engine is running or when engine is in ground hop mode. Contact  with  rotating  fan  can  cause  injury  (reference . - . — FM b. c. d. 21-11). Operate engine at idle. Check  radiator  for  bubbles  in  coolant  which  indicates  a  damaged  cylinder head. Install radiator cap. END  OF  TEST 2 - 1 5