How to Seal a Head Gasket
For a head gasket to seal properly, the head and engine block deck surfaces must be clean, relatively smooth and flat. The presence of any foreign material (dirt, carbon, old gaskets facing material, abrasive residue, etc.) on either surface can prevent a proper seal. Debris can act like a bridge and form pockets that create a path for leakage to occur. Debris can also become embedded in the surface of the gasket. Debris may even damage the surface of the head and/or engine blocks deck surface, which can lead to repeat head gasket failures.