How do you change the thermostat on a 1999 Chrysler Concorde?

You should have the 5.2 engine with your Limited, but some have been ordered with the 4.0. The Thermostat is located on the front of the engine at the end of the Radiator hose. It is between the Alternator, and the A/C Compressor. You might find it easier to remove the Alternator to get to the 2 bolts that hold in the Thermostat Housing. remove them, clean the housing and the surface it sits on, install a new gasket and thermostat and put back anything else you may have taken apart.