We're is the thermostat for my 03 CTS

CTS 2003-2005 Removal Procedure...
3.2L Engines

1. Drain the cooling system.
   
2. Remove the radiator inlet hose from the coolant outlet pipe
   
3. Remove the bolt securing the oil level indicator tube, coolant outlet pipe and engine front lifting bracket from the cylinder head.
   
4. Remove the coolant outlet pipe from the thermostat housing.
   
5. Remove the O-ring seals from the coolant outlet pipe. Discard the O-rings.
   
6. Remove the intake manifold.
   
7. Remove the thermostat housing bolts (1) (image 1 attached)
   
8. Remove the thermostat housing with thermostat (2), from the engine (image 1 attached).
   
9. Remove and discard the seal ring.
   
10. Remove the thermostat from the thermostat housing (image 2 attached).

1. Install the thermostat into the thermostat housing.
   
2. Install a new seal ring.
   
3. Position the thermostat housing with thermostat, to the engine.
   
4. Install the thermostat housing bolts and tighten to 15 ft. lbs. (20 Nm).
   
5. Install the intake manifold.
   
6. Lubricate 2 new O-ring seals with coolant.
   
7. Install the new O-ring seals around the coolant outlet pipe grooves.
   
8. Insert the coolant outlet pipe (3) into the thermostat housing.
   
9. Install the bolt securing the oil level indicator tube, coolant outlet pipe and engine front lifting bracket to the cylinder head and tighten to 15 ft. lbs. (20 Nm).
   
10. Connect the radiator inlet hose to the coolant outlet pipe.
    
11. Fill the cooling system.

Will a bad thermostat keep the car from running or starting