Ford 2003 Mustang Workshop Manual page 1638

17. Disconnect the wiring harness from the valve cover stud bolt.
18. Remove the bolts and the RH valve cover.
19. 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
which make leak paths. Use a plastic scraping tool to remove all traces of old sealant.
Clean and inspect the sealing surfaces and inspect the valve cover gaskets. If necessary, install
new gaskets. Make sure the gaskets are correctly seated on the valve cover.