How do you change riviera thermostat?

It would be nice if you put in the year model. But assuming late model with 3.8 it is very simple. possibly even simpler than changing the oil. It is located at top, and front of engine for most vehicles. Right where the upper radiator hose goes into the motor. Will take a 10mm deep socket, wratchet, and extension. Should have both a paper gasket and rubber o-ring. Be sure and clean all old gasket off the housing, and the intake or it will leak. Their is a bleeder on top of the housing. Unless you have run real low on antifreez you should not have to bleed it.How do you change riviera thermostat?Unbolt it an put in a new one.