Lubricating oil cooler is leaking

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

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.

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

Inspect the air compressor cylinder head and gasket. Refer to Procedure 012-103, Procedure 012-104, and Procedure 012-106 in Section 12.

Cylinder head gasket is leaking

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

Cylinder head is cracked or porous

Remove the intake and the exhaust manifolds. Check for evidence of coolant leaks. If necessary, operate the engine at low idle. Pressure test the cylinder head. Refer to Procedure 002-004 in Section 2.

Cylinder block is cracked or porous

Inspect the cylinder block. Refer to Procedure 001-027 in Section 1.

Cylinder liner is corroded or cracked

Check the cylinder liners for corrosion or cracks. Refer to Procedure 001-027 in Section 1.