M11 Series Engines – Coolant Temperature Above Normal – Sudden Overheat

Symptom Tree  t023

This is symptom tree t023
Cause Correction

Electronic fault codes active or high counts of inactive fault codes

Refer to Section TF in the Troubleshooting and Repair Manual for CELECT™
Plus Systems, Bulletin No. 3666130, or Section TF in the Troubleshooting and Repair Manaul for CELECT™ Systems, Bulletin No. 3666084.


Fan drive belt is broken

Check the fan drive belt. Replace the belt, if necessary. Refer to Procedure 008-002.


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.


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 Procedures 010-027 and 008-042.


Cooling system hose is collapsed, restricted, or leaking

Inspect the radiator hoses. Refer to Procedure 008-045.


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

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


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 Procedure 008-049 and the manufacturer’s instructions.


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 Operation of Diesel Engines in Cold Climates, Bulletin 3379009.


Coolant fill line is not routed correctly

Check the routing of the coolant fill line. Refer to Procedure 008-017 and the OEM specifications.


Coolant fill line is restricted or obstructed

Check the coolant fill line for restrictions or obstructions. Refer to Procedure 008-017 and the OEM specifications.


Fan drive or fan controls are malfunctioning

Check the fan drive and controls. Refer to Procedure 008-024, 008-025, 008-026, 008-027, or 008-028.


Air or combustion gases are entering the cooling system

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


Torque converter cooler disc is not installed correctly

Check the disc for correct installation. Refer to Procedure 008-062.


Cooling system component is malfunctioning

Perform the cooling system diagnostics test. Refer to Procedure 008-020.


Thermostat is not correct or is malfunctioning

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


Water pump is malfunctioning

Check the water pump for correct operation. Replace the water pump if necessary. Refer to Procedure 008-020 and 008-062.

Last Modified:  08-Jan-2004