Ford 2003 Mustang Workshop Manual page 1259

LH cylinder head
57. CAUTION: The cylinder head must be cool before removing it from the engine.
Cylinder head warpage can result if a warm or hot cylinder head is removed.
CAUTION: Place clean shop towels over exposed engine cavities. Carefully remove
the towels so foreign material is not dropped into the engine.
CAUTION: The cylinder head bolts must be discarded and new bolts installed. They
are tighten-to-yield designed and cannot be reused.
CAUTION: Do not use metal scrapers, wire brushes, power abrasive discs or other
abrasive means to clean the sealing surfaces. These tools cause scratches and gouges
that make leak paths. Use a plastic scraping tool to remove all traces of the head gasket.
CAUTION: Aluminum surfaces are soft and can be scratched easily. Never place the
cylinder head gasket surface, unprotected, on a bench surface.
Remove the bolts and the LH cylinder head.
Discard the cylinder head gasket.
Discard the cylinder head bolts.