The only way to fix that problem is to buy a new radiator. Your old one has cracked around the fitting.
The coolant enters the engine by way of the lower radiator hose and exits the engine by way of the upper radiator hose.
Place something to catch the engine coolant beneath your 1990 Chevy Corsica radiator. Remove the radiator drain plug with a 9/16 ratchet. The engine coolant will drain out.
Fill the radiator through the coolant resivour, which is on the passenger side engine compartment.
Connected to the upper radiator hose. Coolant flows from the engine to the radiator to be cooled. The coolant temp. sensor should be screwed into it.
Open the radiator cap when engine is cool. Coolant should be right at the top. If the cooling system is healthy, the coolant reservoir will keep the system full.
It goes in through the lower radiator hose, and out through the upper.
The heater core is stoped up / MAYBE. Are the engine is low on coolant, Check coolant level in radiator.
The coolant temp sensor screws into the thermostat housing. This is located where the top radiator hose connects to the engine.
Follow the upper radiator hose from the radiator to the engine. It will lead you to the thermostat housing. Drain coolant from radiator, remove upper radiator hose from engine, remove the two bolts holding the thermostat housing to engine, remove housing, remove thermostat.
The coolant fan relay on a 1988 Chevy Celebrity with 2.8L V6 is on the radiator support bracket behind the right hand headlights.
there is a drain plug/petcock in one of the corners on the engine side of the radiator. you just have to open that and the coolant will drain out. remember coolant is hazardous to pets as well as the environment.
Pour the coolant in the radiator.