How do you replace the thermostat housing gasket on a 87 Pontiac Sunbird 2.0L OHC?

Drain about 1 gallon of coolant from radiator Follow the upper radiator hose to engine compartment - should end at thermostat housing Remove 2 mounting bolts Remove housing Clean both surfaces Replace gasket Re-Install housing Re-fill coolant slowly to prevent "airlock" Start engine Watch for leaks Run engine to normal operating temperature with heater on Check coolant level