Faulty cylinder head gasket and/or cracking, or other damage to the cylinder head and engine block cooling system passages.

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

• Inspect for spark plugs saturated by coolant.
• Perform a cylinder leak down test.
• Inspect the cylinder head and engine block for damage to the coolant passages and/or a faulty head gasket.
• Repair or replace as required.