ISC, ISCe, QSC8.3, ISL, ISLe3, ISLe4 and QSL9 Engines – Coolant Loss – Internal

Coolant is leaking into the lubricating oil

Check for coolant in the oil. Refer to the Coolant in the Lubricating Oil symptom tree.

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

Check the radiator pressure cap. Refer to Procedure
008-047 (Radiator Pressure Cap) in Section 8.

Lubricating oil cooler is leaking

Check the lubricating oil cooler for coolant leaks. Refer to Procedure
007-003 (Lubricating Oil Cooler) in Section 7.

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

Inspect the air compressor cylinder head and gasket. Refer to Procedure
012-007 (Air Compressor Cylinder Head, Single Cylinder) in Section 12.

Cylinder head gasket is leaking

Check the cylinder head gasket. Refer to Procedure
002-021 (Cylinder Head Gasket) in Section 2.

Coolant is leaking into the combustion chamber

Remove the cylinder head, and inspect the cylinder head, gasket, and pistons for evidence of coolant. Refer to Procedure
002-004 (Cylinder Head) in Section 2.

Cylinder head is cracked or porous

Pressure-test the cylinder head. Refer to Procedure
002-004 (Cylinder Head) in Section 2.

Cylinder head expansion plugs leaking or misassembled

Inspect the cylinder head Procedure
002-004 (Cylinder Head) in Section 2.

Cylinder block is cracked or porous

Remove the oil pan. Pressure-test the cooling system to check for leaks. Refer to Procedure
008-020 (Cooling System Diagnostics) in Section 8.

Aftercooler is leaking

Inspect and pressure-test the aftercooler for leaks. Refer to Procedure
010-005 (Aftercooler Assembly (Sea Water)) in Section 10.