6.7L Cummins Troubleshooting – Coolant in the Lubricating Oil

EGA cooler core is leaking

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

Lubricating oil cooler is malfunctioning

Check the oil cooler. 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 cylinder head and gasket. Refer to Procedure 012-007 in Section 12.
If the air compressor head is not serviceable, replace the air compressor. Refer to Procedure 012-014 in Section 12.

Internal coolant leaks

Refer to Procedure 008-020 in Section 8 to pressure test the cooling system and look for internal coolant leaks.

Variable Geometry Turbocharger leaking coolant

Refer to Procedure 008-020 in Section 8 to pressure test the cooling system and look for internal coolant leaks.

Cylinder head gasket is leaking

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

Cylinder head is cracked or porous

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 001-026 in Section 1.