FEL-PRO is your best bet.
You should use a thermostat gasket along with the thermostat housing ring. The gasket should be replaced every time the thermostat housing is opened.
The housing gasket may be bad. Replace the gasket.
Just the thermostat and the gasket.
Unless the housing is damaged, there is no reason to replace it. Just replace the gasket.
Remove the thermostat housing screws and separate the housing, exsposing the thermostat and coolant, remove old thermostat and gasket. Reinstall new thermostat, gasket and coolant.
thermostat gasket probably leaking. replace thermostat and gasket making sure that thermostat housing is flat.
It's actually easier to replace a Saturn thermostat than most other vehicles. Simply remove the thermostat housing and get a new one. The thermostat is molded into the housing. Remove the radiator hose to the housing, then remove the two nuts that hold the thermostat housing to the engine. You may need to work at breaking the housing loose since the gasket has probably seized to the engine. Simply clean off any left-over gasket, and put the new gasket and thermostat housing in place.
Remove the housing and replace the gasket.
The old thermostat will simply lift out. Drop in the new thermostat. Put a new gasket on the thermostat housing. Secure the thermostat housing with the retaining bolts.
Drain the radiator. The thermostat is in a housing connected to the water pump. Remove the housing to replace the thermostat and gasket.
The Ford puma thermostat housing is on the side of the engine, with two hoses connected to it. Be sure to replace the gasket when installing the housing.
Slightly messy this way... Make sure truck is cold. Unbolt thermostat housing located on the top front of the motor, with the upper radiator hose attached to it. remove housing, remove thermostat. Clean gasket surfaces on intake manifold & thermostat housing. Spread gasket silicone on intake thermostat flange. Install new thermostat, install new gasket on top. Spread gasket silicone on underside of thermostat housing. Bolt housing on intake. Remove radiator cap & top off with 50/50 coolant/water.