TM 10-3930-653-14&P 4-4-2.  TROUBLE DIAGNOSES AND CORRECTIONS Condition Probable cause Corrective action Loss of water Damaged radiator seams Repair Leaks at heater connections or plugs Repair Leak at water temperature gauge Tighten Loose joints Tighten Damaged cylinder head gasket Replace Check   engine   oil   for   contamination   and   refill   as necessary Cracked cylinder block Replace. Check engine oil in crankcase for mixing with water by pulling oil level gauge Cracked cylinder head. Replace Loose cylinder head bolts Tighten Poor circulation Restriction in system Check  hoses  for  crimps,  and  clear  the  system  of rust and sludge by flushing radiator. Insufficient coolant Replenish Inoperative water pump Replace Loose fan belt Adjust Inoperative thermostat Replace Corrosion Excessive impurity in water Use soft, clean water.  (Rain water is satisfactory ) Infrequent flushing and draining of system Cooling   system   should   be   drained   and   flushed periodically.  Permanent anti freeze (Ethylene glycol base)  can  be  used  throughout  the  seasons  of  the year, and changed periodically at intervals recommended Overheating Inoperative thermostat Replace Radiator fin choked with mud, chaff, etc Clean   out   air   passage   thoroughly   by   using   air pressure from engine side of radiator Incorrect ignition and valve timing Adjust. Dirty oil and sludge in engine Refill Inoperative water pump. Replace Loose fan belt Adjust Restricted radiator Flush radiator Inaccurate temperature gauge. Replace Impurity in water Use soft, clean water Overcooling. Inoperative thermostat Replace. Inaccurate temperature gauge Replace. 4-57