Coolant in Engine Oil (1)

Engine Mechanical - 5.3L L84 or 6.2L L87 | Diagnostic Information and Procedures | Document ID: 5600962 Coolant in Engine Oil Coolant in Engine Oil

Cause DEFINITION: Foamy or discolored oil or an engine oil “overfill” condition may indicate coolant entering the engine crankcase. Low coolant levels, an inoperative cooling fan, or a faulty thermostat may lead to an “overtemperature” condition which may cause engine component damage. Contaminated engine oil and oil filter should be changed. 1. Inspect the oil for excessive foaming or an overfill condition. Oil diluted by coolant may not properly lubricate the crankshaft bearings and may lead to component damage. Refer to Lower Engine Noise, Regardless of Engine Speed. 2. Inspect by performing a cylinder leak-down test. During this test, excessive air bubbles within the cooling system may indicate a faulty gasket or damaged component. 3. Inspect by performing a cylinder compression test. Two cylinders “side-by-side” on the engine block with low compression may indicate a failed cylinder head gasket. Engine Compression Test	Correction
Faulty external engine oil cooler	Replace the components as required.
Faulty cylinder head gasket	Replace the head gasket and components as required. Cylinder Head Replacement - Left Side Cylinder Head Replacement - Right Side Cylinder Head Overhaul
Warped cylinder head	Machine the cylinder head to proper flatness, if applicable, and replace the cylinder head gasket. Cylinder Head Overhaul
Cracked cylinder head	Replace the cylinder head and gasket.
Cracked cylinder liner or engine block	Replace the components as required.
Cylinder head, block, or manifold porosity	Replace the components as required.