Ford 2003 Mustang Workshop Manual page 1860

14. Install the air intake scoop. For additional information, refer to
Bleeding
1. Select the maximum heater temperature and blower motor speed settings. Position the control
to discharge air at A/C vents in instrument panel.
2. Start the engine and allow to idle. While engine is idling, feel for hot air at A/C vents.
3. CAUTION: If the air discharge remains cool and the engine coolant temperature
gauge does not move, the engine coolant level is low and must be filled. Stop the engine,
allow the engine to cool and fill cooling system.
Start the engine and allow it to idle until normal operating temperature is reached. Hot air should
discharge from A/C vents. The engine coolant temperature gauge should maintain a stabilized
reading in the middle of the NORMAL range. The upper radiator hose should feel hot to the
touch.
4. Shut the engine off and allow the engine to cool.
5. Check the engine for coolant leaks.
6. Check the engine coolant level in the degas bottle/coolant expansion tank and fill as necessary.
Section 303-12 .