1992 Chevy Corsica 3.1 liter keeps overheating?

Just went thru this, was the radiator. Best way is to have your cooling system pressure tested. We replaced the radiator, upper hose, lower hose and a bad thermostat. Later our water pump failed, and then the heater core. I have replaced the whole cooling system, and would be happy to help you with any future questions. T HEMPLE