How do you change a thermostat on a 1997 Pontiac Grand Am?

Should be located in a removable housing at the engine end of the upper radiator hose Drain about 1 gallon of coolant from radiator

Remove housing

Make note how thermostat is installed

Clean both surfaces

Replace thermostat and gasket

Re-fill coolant slowly to prevent an air lock

Start engine and look for leaks

Run engine to normal operating temperature with heater on

Re-check coolant level