Thermostat location for replacement?

Yes, as the diagram below shows, there are two bolts needing to be removed from the thermostat housing.

The thermostat gasket is the kind of thick round gasket on this vehicle, that is it.

On a 3.4 the thermostat is on the far right side while standing in front of the vehicle, below the intake. You will need to remove the exhaust crossover and some coolant tubing from the top of the engine to get to it.

3.8L
Drain about 1 gallon of coolant from radiator
Locate removable housing a the engine end of the upper radiator hose and remove
Note how thermostat is installed in housing
Clean both surfaces
Install new thermostat and gasket
Re-fill coolant slowly to prevent an air lock
Start engine and look for leaks
Run engine to normal operating temperature with heater on
Re-check coolant level

Carefully remove the throttle body air inlet duct.
Partially drain the cooling system. Refer to Draining and Filling Cooling System.
Use the J 38185 in order to reposition the hose clamp at the thermostat housing.
Disconnect the radiator hose from the thermostat housing.
Remove the exhaust crossover pipe. Refer to Exhaust Crossover Replacement.
Remove the thermostat housing bolts.
Remove the thermostat housing and the gasket.
Remove the thermostat.
Clean the mating surfaces.

Depends on engine size. Here are your two options.

The last one is for a 3.8l v6
The first two are for the 3.4l v6

THERMOSTAT

Removal

1. Remove the air cleaner intake duct.

2. Partially drain the cooling system.

3. Use the Hose Clamp Pliers (J 38185) to reposition the hose clamp from the water outlet housing.

4. Remove the radiator inlet hose from the water outlet housing.

5. Remove the exhaust crossover pipe.

6. Remove the water outlet housing bolts.

7. Remove the water outlet housing and the gasket.

8. Remove the thermostat.

9. Clean the water outlet mating surfaces.

Installation

1. Install the thermostat.

2. Install the water outlet gasket and housing.

3. Install the water outlet housing bolts. Tighten the bolts to 25 N.M (18 ft lbs).

4. Install the exhaust crossover pipe.

5. Install the radiator inlet hose to the water outlet housing.

6. Use the Hose Clamp Pliers to reposition and install the hose clamp to the water outlet housing.

7. Install the air cleaner intake duct.

8. Fill the cooling system. Refer to COOLING SYSTEM BLEEDING.

COOLING SYSTEM BLEEDING

1. Open air bleed screw located on thermostat housing 2-3 turns. Slowly fill cooling system through radiator neck to base of radiator neck. Wait 2 minutes. Recheck fluid level. Add coolant to restore level to base of radiator neck.

2. Install radiator cap. Close air bleed screw. Fill coolant reservoir with 1 quart (.95L) of coolant.

NOTE:
The Low Coolant warning/indicator lamp may come on after this procedure. If after operating the vehicle so that the engine heats up and cools down three times, the Low Coolant warning/indicator lamp does not go out, or fails to come on at the ignition check, and the coolant is above the full cold mark in the reservoir, refer to Low Coolant Warning/Indicator Lamp in Electrical Diagnosis. If at any time the Temperature warning/indicator lamp comes on, immediate action is required. Turn OFF the engine and allow the vehicle to cool. Do not remove the coolant recovery reservoir cap at this time.