Centinel System – Repair Manual – Coolant Loss – Internal

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 t00-004 in Section TS. If the truck is equipped with an Auxiliary Power Unit, make sure the unit is not leaking..

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.

EGR cooler core is leaking

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

Aftertreatment fuel injector is leaking coolant

Check the aftertreatment fuel injector for coolant leaks. Refer to Procedure 011-061 in Section 11.

Injector Sleeve is leaking – even with no noticeable defect to the injector o-rings

Replace the injector o-rings and install and tighten the injectors again to reseat the injector cups. Return the engine to operation. Refer to
Procedure 006-026 in Section 6.

First investigated instance of internal coolant loss

For the first investigated instance of internal coolant loss, perform the corrections in the steps above and then stop here. Return the engine to operation and check for continuing leaks. If the leaks continue, complete the remaining steps of this tree.

Lubricating oil cooler is leaking

Check the lubricating oil cooler for coolant leaks. Refer to
Procedure 007-003 in Section 7.

Air compressor cylinder head is cracked or porous, or has a leaking gasket

Inspect the air compressor air inlet and outlet tubes for signs of coolant. Refer to Procedure 012-007 in Section 12.

Air compressor cylinder head is cracked or porous, or has a leaking gasket

Inspect the air compressor cylinder head and gasket. Refer to
Procedure 012-003 in Section 12.

Turbocharger leaking coolant

If the unit is equipped with a water cooled turbocharger, refer to
Procedure 010-033 in Section 10.

Fuel heater is leaking coolant

If applicable, check the fuel heater for coolant leaks. Refer to the OEM service manual.

Transmission oil cooler or torque converter cooler is leaking

If applicable, check the transmission oil cooler and torque converter cooler for coolant leaks. Refer to the OEM service manual.

Cylinder head gasket is leaking

Check the cylinder head gasket. Refer to
Procedure 002-004 in Section 2.

Cylinder head is cracked or porous

Pressure test the cylinder head. Refer to
Procedure 002-004 in Section 2.

Base engine problem

Refer to Cummins Inc. and request additional technical assistance.