Cummins ISX11.9 CM2250 – Service Manual Coolant Temperature Above Normal – Gradual Overheat

Electronic fault codes active or high counts of inactive fault codes

Refer to Section TF in the Fault Code Troubleshooting Manual, Bulletin
4022225.

Coolant level is below specification

Inspect the engine and cooling system for external coolant leaks. Repair if necessary. Add coolant. Refer to
Procedure 008-018 in Section 8
.

Cold weather radiator cover or winterfront is closed

Open the cold weather radiator cover or the winterfront. Maintain a minimum of 784 cm² [122 in²] or approximately 28 x 28 cm [11 x 11 in] of opening at all times. Refer to Procedure 101-004 in Section 1 of the Operation and Maintenance Manual, Bulletin 2883444.

Fan drive belt is loose

Check the automatic belt tensioner. Refer to Procedure 008-002 and
Procedure 008-087 in Section 8.

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 in Section 10,
Procedure 008-042 in Section 8, and the OEM service manual.

Fan drive or fan controls are malfunctioning

Check the fan drive and controls. Refer to
Procedure 008-027 in Section 8
.

Radiator cap is not correct, is malfunctioning, or has low-pressure rating

Check the radiator pressure cap. Refer to
Procedure 008-047 in Section 8
.

Radiator shutters are not opening completely, or the shutterstat setting is wrong

Inspect the radiator shutters. Repair or replace if necessary. Check the shutterstat setting. Refer to the OEM service manual.

Coolant temperature gauge is malfunctioning

Test the temperature gauge. Repair or replace the gauge, if necessary. Contact a Cummins® Authorized Repair Location.

Cooling system hose is collapsed, restricted, or leaking

Inspect the hoses. Refer to
Procedure 008-045 in Section 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, as necessary. Refer to Procedure 008-038 in Section 8 and the OEM service manual.

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 Procedure 008-017 in Section 8 and the OEM service manual.

Thermostat is not correct or is malfunctioning

Check the thermostat for the correct part number and for correct operation. Refer to
Procedure 008-013 in Section 8
.

Intake manifold air temperature is above specification

Refer to the Intake Manifold Air Temperature Above Specification symptom tree.

Lubricating oil level is above or below specification

Check the oil level. Add or drain oil, if necessary. Refer to Procedure 007-037 in Section 7. Check the dipstick calibration. Refer to
Procedure 007-009 in Section 7.

Radiator swing check valve is malfunctioning (if equipped)

Check the swing check valve for correct operation. Refer to the OEM service manual.

Water pump is malfunctioning

Check the water pump. Replace the water pump if necessary. Refer to
Procedure 008-062 in Section 8
.

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 in Section 8
.

Check valve is damaged (with remote-mounted engine coolant heater)

Inspect the check valve. Replace if necessary. Refer to the OEM service manual.

Air or combustion gases are entering the cooling system

Check for air or combustion gases in the cooling system. Refer to
Procedure 008-019 in Section 8
.

Torque converter is malfunctioning

Check the torque converter. Refer to the OEM service manual.

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.