N14 Base Engine Troubleshooting and Repair Manual – Coolant in the Lubricating Oil

Symptom Tree  t025

This is symptom tree t025
Cause Correction

Lubricating oil cooler is leaking

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


Air or combustion gases are entering the cooling system

Check for air or combustion gases in the cooling system. Refer to Procedure 008-019.


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

Inspect the air compressor cylinder head and gasket. Refer to Procedures 012-103, 012-104, and 012-106.


Cylinder head gasket is leaking

Check the cylinder head gasket. Refer to Procedure 002-021.


Cylinder head is cracked or porous

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


Cylinder block is cracked or porous

Inspect the cylinder block. Refer to Procedure 001-027.


Cylinder liner is corroded or cracked

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

Last Modified:  05-Jan-2004