Ford 2W9Z-8575-AB
Thermostat

Begin service and repair of the thermostat within the 3.9L engine by draining coolant first before removing the engine appearance cover along with the air cleaner outlet tube. Read and follow the specified order of removing separate components according to the illustrated instructions. Reinstall the unit according to the reverse order used for removal and properly fill the cooling system after bleeding it. To detach the thermostat users should rotate it in both directions while utilizing an 18 mm open-end wrench to lower and unlock the retainer from the housing. When installing the thermostat spring position the small section of the spring toward the thermostat housing. The installation process requires you to orient the thermostat pin in the housing hole while verifying that the tabs of the retainer snap into slots inside the thermostat housing. To install the thermostat users should employ an 18 mm open-end wrench for pushing down while rotating the retainer until the thermostat fits properly into position.

Begin by draining the cooling system and removing the thermostat housing.

Confirm that the tabs on the thermostat retainer are locked into the tabs on the housing.

The thermostat can be rotated in either direction to release it; use an 18 mm (0.7 inch) open end wrench to simultaneously push down and turn the thermostat retainer for removal.