Ford 2003 Mustang Workshop Manual page 1468

Plug the coolant connections.
Flush the oil passages with parts cleaner. If metal particles are present in the oil cooler,
install a new cooler.
7. Remove the oil filter adapter.
1. Remove the bolts.
2. Remove the oil filter adapter.
3. Remove the gasket.
8. Clean and inspect the oil filter adapter.
Flush the oil filter adapter with parts cleaner. If metal particles are present in the adapter,
install a new adapter.
9. To install, reverse the removal procedure.