COOLING SYSTEMCOOLING SYSTEMTM 5-3805-258-24-1T E S T I N G A N D A D J U S T I N GThe engine has a pressure type cooling system. Apressure type cooling system gives two advantages.The first advantage is that the cooling system canoperate safely at a temperature that is higher thanthe normal point where water changes to steam. Thesecond advantage is that this type system preventscavitation (air in inlet of pump) in the water pump.With this type system it is more difficult for an air orsteam pocket to form in the cooling system.The cause for an engine getting too hot is generallybecause regular inspections of the cooling systemwere not done. Make a visual inspection of the cool-ing system before testing with testing equipment,VISUAL INSPECTION OF THE COOLINGSYSTEM1.2.3.4.5.6.7.8.Check coolant level in the cooling system.Look for leaks in the system.Look for bent radiator fins. Be sure that air flowthrough the radiator does not have a restriction.Inspect the drive for the fan.Check for damage to the fan blades.Look for air or combustion gas in the coolingsystem.Inspect the pressure cap and the sealing surfacefor the cap. The sealing surface must be clean.Look for large amounts of dirt in the radiatorTest Tools for Cooling SystemTools Needed:9S9102 Thermistor Thermometer Group.9S7373 AirMeter Group.6V3121 Multitach Group.9S8140 Cooling System Pressurizing Pump Group.The 9S9102 Thermistor Thermometer Group isused in the diagnosis of overheating (engine runningtoo hot) or overcooking (engine runs too cool) prob-lems. This group can be used to check temperaturesin several different parts of the cooling system.9S9102 THERMISTOR THERMOMETER GROUPcore and on the engine.TESTING THE COOLING SYSTEMRemember that temperature and pressure worktogether. When making a diagnosis of a coolingsystem problem, temperature and pressure mustboth be checked. Cooling system pressure will havean effect on cooling system temperatures. For anexample, look at the chart to see the effect of pressureand the height above sea level on the boiling point(steam) of water.A32417.2X1C O O L I N G S Y S T E M P R E S S U R EALTITUDEMSTSXSFEIH432a14,0M37001 Z,ooo30W10, OOO24008,000mm9 S 7 3 7 3 A I R M E T E R G R O U Ps.moI 2W4.ocaThe 9S7373 Air Meter Group is used to check thew2.000SSA LSVEL Oair flow through the radiator core.82M9349IM110I 15121”C140120 200210220 330240250- FBOILING POINT OF WATER4-31
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