Drain the cooling system below the level of the coolant outlet housing.
Fig. 1: Exploded view of the thermostat assembly for 2.3L and 2.5L engines
Disconnect the heater return hose at the thermostat housing located on the left front lower side of engine.
Remove the coolant outlet housing retaining bolts and slide the housing with the hose attached to one side.
Remove the thermostat from the outlet.
Remove the gasket from the engine block and clean both mating surfaces.
It is good practice to check the operation of a new thermostat before it is installed in an engine. Place the thermostat in a pan of boiling water. If it does not open more than 1/4 in., do not install it in the engine.
Coat a new gasket with water resistant sealer and position it on the outlet of the engine. The gasket must be in place before the thermostat is installed.
Install the thermostat with the bridge (opposite end from the spring) inside the elbow connection and turn it clockwise to lock it in position, with the bridge against the flats cast into the elbow connection.
Position the elbow connection onto the mounting surface of the outlet, so that the thermostat flange is resting on the gasket and install the retaining bolts.
Connect the heater hose to the thermostat housing.
Fill the radiator and operate the engine until it reaches operating temperature. Check the coolant level and adjust as necessary.