My 1998 century over heats - 1998 Buick Century

Check condition and operation of thermostat.
Check operation of radiator cooling fan when hot.
Check radiator coolant level. If low, then perform a cooling system pressure check to identify cause of leak.
Check coolant condition. If using water only, then corrosion may build up within system and cause blockages. If blocked, then flush system and refill with anti freeze-water mixture of 50/50.