How do you replace heater core in a 1990 cutla ciera Oldsmobile?

Answer 1

1. Disconnect the negative battery cable and drain the cooling system.

2. Disconnect the heater hoses from the heater core inlet and outlet connections in the engine compartment.
3. Allowing residual coolant from the heater core to drain. Cap the openings.
4. Working inside the vehicle, remove the lower instrument panel sound insulator.
5. Remove the heater floor outlet duct screws or clips and remove the duct.
6. Remove the heater core cover by removing the attaching screws and clips.
7. Remove the heater core cover.
8. Remove the heater core retainers and remove the heater core.