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TM 10-3930-671-24
4.8. Cooling System
Cooling System Troubleshooting ........................................ .............................F-93
Engine Coolant Specification ........................................ ...................................F-94
Engine Coolant Level Check ............................................................................F-94
General Procedures ........................................ .................................................F-94
Cooling System Inspection ...............................................................................F-95
Cooling System Pressure Tests .......................................................................F-96
Engine Coolant Change ...................... ............................................................F-97
Fan ...................................................................................................................F-98
Cooling Fan Installation ....................................................................................F-99
Fan Belt .............................................................................................................F-99
Fan Belt Tensioning ..........................................................................................F-99
Fan Belt Tension Specification........................................................................F-100
Cooling System ...............................................................................................F-100
Transmission Cooling Lines ............................................................................F-101
Cooling System Troubleshooting
It is important to control the temperature range of the coolant in order to maintain best engine efficiency. The efficiency of
the cooling system can be affected by any of the following:
Engine Running Too Hot
•
Coolant level is low.
•
Plugged radiator (internal or external).
•
Faulty radiator cap.
•
Fan belt slipping.
•
Fan blades reversed.
•
Defective viscous fan drive.
•
Damaged or collapsed coolant hoses.
•
Missing or damaged fan shroud or shields
on radiator.
•
Air entrained in cooling system.
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Ignition timing late or severely retarded.
•
Excessive exhaust system back pressure.
•
Missing or improperly adjusted exhaust
tailpipe.
•
Engine oil level is low.
•
Engine oil needs changing.
•
Faulty thermostat.
•
Defective temperature gauge.
•
Clogged water passages in engine.
•
Worn or broken water pump.
•
Worn internal engine parts.
•
Leaking head gasket.
•
Engine being overloaded.
•
Brakes dragging.
•
Transmission fluid level low.
•
Transmission slipping.
•
Transmission damaged or improperly
adjusted.
•
Locked converter stator.
Engine Running Too Cold
•
Faulty thermostat.
•
Defective temperature gauge.
Oil In Coolant or Coolant In Crankcase
•
Leaking head gasket.
•
Cylinder head bolts not tight.
•
Cylinder head cracked.
•
Engine cylinder block water jackets cracked.
•
Cylinder liner seals leaking
(when applicable).
•
Transmission oil cooler leak.
Water Pump Leaking
•
Worn or broken water pump gasket.
•
Worn pump shaft and/or seal.
•
Pump body cracked or damaged.
Water Pump Making Noise
•
Worn pump shaft or bearings loose or worn.
•
Pump impeller broken.
•
Loose fan belt.
•
Bent or broken fan blade.
•
Fan hitting engine or shroud.
F-93
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