N14 Base Engine Troubleshooting and Repair Manual – Coolant Temperature Above Normal – Gradual Overheat

Electronic fault codes active or high counts of inactive fault codes

Refer to Section TF in the Troubleshooting and Repair Manual, CELECT™ Plus Systems, Bulletin 3666130, or Section TF in the Troubleshooting and Repair Manual, CELECT™ Systems, Bulletin 3666084, for fault code troubleshooting.

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.

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 the OEM service manual.

Cooling system hose is collapsed, restricted, or leaking

Inspect the hoses. Refer to Procedure 008-045.

Fan drive belt is loose

Check the belt tension and tighten if necessary. Refer to Procedure 008-002.

Lubricating oil level is above or below specification

Check the oil level. Add or drain oil, if necessary. Refer to Procedures 007-037 and 007-009..

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 and the OEM service manual.

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

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

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. Procedure 008-047

Intake manifold temperature gauge is malfunctioning, if equipped

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

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.

Thermostat is not correct or is malfunctioning

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

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

Inspect the radiator shutters. Repair or replace if necessary. Refer to Procedure 008-049. Check the shutterstat setting.

Radiator swing check valve is malfunctioning (if equipped)

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

Fan drive or fan controls are malfunctioning

Check the fan drive and controls. Refer to Procedure 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.

Water pump is malfunctioning

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

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 the OEM service manual.

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

Inspect the check valve. Replace if necessary. Refer to the manufacturer’s instructions.

Engine is overfueled

Check the engine fuel rate. Refer to Procedure 014-005.

Vehicle cooling system is not adequate

Verify that the engine and vehicle cooling systems are using the correct components. Refer to the OEM specifications.

Torque converter cooler disc is not installed correctly

Check the disc for correct installation. Refer to the OEM service manual.