Cause Correction
STEP 1
Electronic fault codes active or high counts of inactive fault codes
...
Read the fault codes with an electronic service tool. Refer to Section TF in Troubleshooting and Repair Manual, ISB, QSB4.5, QSB5.9, QSB6.7, ISC, QSC8.3, ISL and QSL9 Engines, CM850 Electronic Control System, Bulletin 4021416 or Troubleshooting and Repair Manual, Electronic Control System, ISC, QSC8.3 and ISL Engines, Bulletin 3666271.
OK Go To Next Step
STEP 2
Fan drive or fan controls are malfunctioning ... Check the fan drive and controls. Refer to Procedure 008-027.
OK Go To Next Step
STEP 3
Cold weather radiator cover or winterfront is closed ...
Open the cold weather radiator cover or the winterfront. Maintain a minimum of 384 cm2 [60 in2] or approximately 19.6 x 19.6 cm [7.5 x 7.5 in]
of opening at all times.
OK Go To Next Step
STEP 4
Charge air cooler fins, radiator fins, or air conditioner condenser fins are damaged or
obstructed with debris
...
Inspect the charge air cooler, air conditioner condenser, and radiator fins. Clean, if necessary.
Refer to Procedure 010-027 and the OEM service manual.
OK Go To Next Step
STEP 5
Coolant level is below specification ...
Inspect the engine and cooling system for external coolant leaks. Repair if necessary. Add coolant.
Refer to Procedures 008-018 and 008-020.
OK Go To Next Step
STEP 6
Coolant mixture of antifreeze and water is not correct
...
Verify the concentration of antifreeze in the coolant. Add antifreeze or water to correct the concentration. Refer to the Cummins Coolant Requirements and Maintenance, Bulletin 3666132.
OK Go To Next Step
STEP 7
Sea water cooling system is malfunctioning ...
Troubleshoot the sea water system. Refer to the Coolant Temperature Above Normal - Sea Water Cooling System symptom tree.
OK Go To Next Step
ISC, ISCe, QSC8.3, ISL, ISLe3, [...] Troubleshooting Symptoms Charts
Section TS - Troubleshooting Symptoms Page TS-19
Coolant Temperature Above Normal - Gradual Overheat
This is symptom tree t022Cause Correction
STEP 8
Fan shroud is damaged or missing or the air recirculation baffles are damaged or missing
...
Inspect the shroud and the recirculation baffles.
Repair, replace, or install, if necessary. Refer to Procedure 008-038.
OK Go To Next Step
STEP 9
Fan drive belt is broken or loose ... Check the fan drive belt. Replace the belt if necessary. Refer to Procedure 008-002.
OK Go To Next Step
STEP 10
Keel cooler or heat exchanger is malfunctioning or not adequately sized
... Refer to Procedures 008-052, 008-053 or 008-083.
OK Go To Next Step
STEP 11
Coolant temperature gauge is malfunctioning ...
Test the temperature gauge. Repair or replace the gauge, if necessary. Refer to the OEM service manual.
OK Go To Next Step
STEP 12
Radiator cap is not correct, is malfunctioning, or has low-pressure rating
... Check the radiator pressure cap. Refer to Procedure 008-047.
OK Go To Next Step
STEP 13
Thermostat is not correct or is malfunctioning ...
Check the thermostat for the correct part number and for correct operation. Refer to Procedure 008-013 for ISC, QSC8.3 (industrial and marine engines), ISL, and QSL9 industrial engines, or Procedure 008-014 for QSL9 marine keel cooled engines.
OK Go To Next Step
STEP 14
Cooling system hose is collapsed, restricted, or leaking
... Inspect the hoses. Refer to Procedure 008-045.
OK Go To Next Step
STEP 15
Fill line or vent lines are restricted, obstructed, or not routed correctly
...
Check the vent lines and the fill line for correct routing and for restriction. Refer to the OEM service manual.
OK Go To Next Step
Troubleshooting Symptoms Charts ISC, ISCe, QSC8.3, ISL, ISLe3, [...]
Page TS-20 Section TS - Troubleshooting Symptoms
Coolant Temperature Above Normal - Gradual Overheat
This is symptom tree t022Cause Correction
STEP 16
Intake manifold air temperature is above specification
... Refer to the Intake Manifold Air Temperature Above Specification symptom tree.
OK Go To Next Step
STEP 17
Lubricating oil level is above or below specification ... Check the oil level. Add or drain oil, if necessary.
Refer to Procedure 007-009.
OK Go To Next Step
STEP 18
Cooling system is contaminated with dirt, scale, or sludge
... Clean the cooling system. Refer to Procedure 008-018.
OK Go To Next Step
STEP 19
Lubricating oil is contaminated with coolant or fuel ... Refer to the Lubricating Oil Contaminated symptom tree.
OK Go To Next Step
STEP 20
Coolant is contaminated with lubricating oil ... Refer to the Lubricating Oil or Transmission Oil in Coolant symptom tree.
OK Go To Next Step
STEP 21
Coolant pump is malfunctioning ...
Check the water pump for correct operation.
Replace the water pump, if necessary. Refer to Procedure 008-062.
OK Go To Next Step
STEP 22
Radiator core is internally obstructed or damaged, or the check valve or J-tube is malfunctioning
... Inspect the radiator and clean if necessary. Refer to Procedure 008-042.
OK Go To Next Step
STEP 23
Torque converter is malfunctioning ... Check the torque converter. Refer to the OEM service manual.
OK Go To Next Step
STEP 24
Torque converter cooler or hydraulic oil cooler is malfunctioning
... Remove and inspect the cooler cores and o-rings.
Refer to the OEM service manual.
OK Go To Next Step
ISC, ISCe, QSC8.3, ISL, ISLe3, [...] Troubleshooting Symptoms Charts
Section TS - Troubleshooting Symptoms Page TS-21
Coolant Temperature Above Normal - Gradual Overheat
This is symptom tree t022Cause Correction
STEP 25
Vehicle cooling system is not adequate ...
Verify that the engine and vehicle cooling systems are using the correct components. Refer to the OEM service manual.
OK Go To Next Step
STEP 26
Air or combustion gases are entering the cooling system
... Check for air or combustion gases in the cooling system. Refer to Procedure 008-020.
OK Go To Next Step
STEP 27
Cylinder head gasket is leaking ... Check the cylinder head gasket. Refer to Procedure 002-021.
OK Go To Next Step
STEP 28
Engine is overfueled ... Check the engine fuel rate. Refer to the Fuel Consumption Excessive symptom tree.
OK Go To Next Step
STEP 29
Plugged cooling passages in the cylinder head, head gasket, or cylinder block
... Pressure-test the cooling system. Refer to Procedure 008-020.
Troubleshooting Symptoms Charts ISC, ISCe, QSC8.3, ISL, ISLe3, [...]
Page TS-22 Section TS - Troubleshooting Symptoms