Centinel System – Repair Manual – Coolant Loss – External

Excessive internal or external engine coolant loss

Before troubleshooting, it is important to determine the exact complaint by interviewing the driver, looking at the service history, and looking at the ECM information. Refer to the Coolant Loss Pre-Troubleshooting Guide at the end of Section TS.

Coolant level is above specification

Check the coolant level. Refer to the OEM service manual.

External coolant leak

Inspect the engine for coolant leaking from hoses, draincocks, water manifold, expansion and pipe plugs, fittings, radiator core, exhaust heat shield, heat exchanger, air compressor and cylinder head gaskets, lubricating oil cooler, water pump seal, and OEM-mounted components that have coolant flow. If necessary, pressure-test the cooling system, exhaust heat shield, or heat exchanger. Refer to Procedure 008-018 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.

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 restrictions. Refer to the OEM service manual.

Cooling system hose is collapsed, restricted, or leaking

Inspect the hoses. Refer to Procedure 008-045 in Section 8.

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.

Engine is overheating

Refer to the Coolant Temperature Above Normal – Gradual Overheat and Coolant Temperature Above Normal – Sudden Overheat symptom trees.

Turbocharger leaking coolant

Check the turbocharger bearing housing. Refer to Procedure 010-033 in Section 10.

EGR valve leaking coolant

Check the EGR valve assembly. Refer to Procedure 011-022 in Section 11.

EGR cooler leaking coolant

Check the EGR cooler for leaks. Refer to Procedure 011-019 in Section 11.