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TROUBLESHOOTING
Page 63
ENGINE OVERHEATS
HIGH EXHAUST TEMPERATURE
Possible Cause
Correction
1. Coolant level low.
1. Locate cause. Look for leaking gaskets or loose or leaking hoses.
Repair, replace or tighten as required. Replenish coolant.
2. Loose or worn fan belts.
2. Adjust belt tension or replace belts as required.
3. Restricted airflow through radiator.
3. Remove any restrictions from the outer surface of the radiator.
4. Plugged radiator core.
4. Remove, repair or replace radiator as required.
5. Defective radiator pressure cap.
5. Test pressure of the radiator cap. Replace cap if required.
6. Defective coolant thermostat or temperature
gauge.
6. Check opening temperature of thermostat. Check for correct
installation. Check temperature gauge and sending unit. Replace
if defective.
7. Viscous (or ON/OFF) fan drive not operating
properly, or fan improperly positioned.
7. Check fan operation. Repair as required.
8. Combustion gases in coolant.
8. Determine point where gases are entering the cooling system.
Repair or replace parts as required.
9. Defective water pump.
9. Remove, repair and reinstall water pump as required.
10. Plugged oil cooler.
10. Remove oil cooler. Disassemble, remove restrictions/replace
parts as required. Reinstall.
11. Winterfront (if equipped) not opened.
11. Open or remove winterfront at specified ambient temperatures.
12. Shutters not opening properly (for chassis
equipped with shutters).
12. Check shutter operation. Repair as required.
Possible Cause
Correction
1. Operating chassis in wrong gear ratio for load,
grade and/or altitude.
1. Instruct operator on correct gear selection for load and grade
conditions.
2. Restrictions in the air induction system.
2. Inspect air induction system. Remove restrictions and/or replace
defective parts.
3. Air leaks in the air induction system.
3. Check pressure in the air intake manifold. Look for leaking piping
and/or loose clamps. Make necessary repairs.
4. Leaks in the exhaust system (before the
turbocharger).
4. Check exhaust system for leaks. Make necessary repairs.
5. Restrictions in the exhaust system.
5. Inspect system. Make necessary repairs.
6. Improper valve lash adjustment.
6. Adjust valve lash setting to specified clearance.
7. Defective fuel injection nozzle assembly.
7. Isolate defective nozzle. Refer to item 8 in ENGINE MISFIRES —
NO CODE(S) chart.
High Pyrometer — Normal Boost
8. Loose ducting.
8. Repair loose connections.
9. Intercooler core fin obstructions.
9. Clean intercooler fins.
High Pyrometer — Low Boost
10. Intercooler core leakage.
10. Pressure-test intercooler. Remove, repair or replace intercooler if
test results are unsatisfactory.
11. Dirty turbocharger.
11. Remove turbocharger and clean.
12. Leaks in the pressurized side of the air
induction system.
12. Check for leaks. Repair as required.
13. Blockage in ducting between the air cleaner
and the turbocharger.
13. Check for blockage and repair.
5_106_00.bk Page 63 Friday, August 4, 2000 11:17 AM
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