Faulty cylinder head gaskets and/or cracking or other damage to the cylinder heads and engine block cooling system passages

Refer to Diagnostic Starting Point - Engine Cooling in Engine Cooling.

Coolant consumption may or may not cause the engine to overheat.

1. Inspect for spark plugs saturated by coolant. Refer to Spark Plug Inspection in Engine Controls - 6.0L.
2. Perform a cylinder leak down test. Refer to Cylinder Leakage Test .
3. Inspect the cylinder heads and engine block for damage to the coolant passages and/or a faulty head gasket. Refer to Coolant in Combustion Chamber .
4. Repair or replace, as required.