2005 Chevy Cavalier thermostat

I belive it is where the upper radiator hose is attached to the engine, there will be about two bolts and a little housing, if you dont see nothing just the plain engine block check the lower hose.

4 cylinder with 2.2 l
thermostat is located under the exhaust manifold
and in the water pump feed pipe
for replacement you need to remove exhaust manifold

When you remove the manifolds it might be best to loosen the bolts just enough to prevent breaking them. Then retighten and torque them and ltet the vehicle cool overnight.

Next day you should be good to remove it. That way the manifold dont warp.