ISM, ISMe, and QSM11 – Coolant Temperature Below Normal

Symptom Tree  t024

This is symptom tree t024
Cause Correction

Coolant temperature gauge is malfunctioning

Test the temperature gauge. Repair or replace the gauge, if necessary. Refer to Procedure 008-004 and the OEM service manual.


Engine is operating at low ambient temperature

Check the winterfront, shutters, and under-the-hood air. Use under-the-hood intake air in cold weather. Refer to Operation of Diesel Engines in Cold Climates, Bulletin 3379009, and the Operation and Maintenance Manual ISM and ISMe Engines, Bulletin 3666319.


Coolant fill line is not routed correctly

Check the routing of the coolant fill line. Refer to the OEM service manual.


Radiator shutters are stuck open or opening early

Check the shutter operation. Repair or replace the shutters if necessary. Refer to Procedure 019-019 in the Troubleshooting and Repair Manual CELECT™ Plus System, Bulletin 3666130.


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.


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.


Thermostat seal is damaged, missing, or not installed correctly

Check the thermostat seal. Check the thermostat for correct seating. Refer to Procedure 008-013 or 008-016.


Coolant flow through the radiator is not correct

Check for correct coolant flow through the radiator. Refer to Procedure 008-042.

Last Modified:  16-Jan-2004