How do you replace heater core on 1989 Oldsmobile ninety eight regency?

To replace the heater core on a 1989 Oldsmobile Ninety Eight Regency, start by removing the dashboard and the center console to access the heater core housing. Drain the coolant from the radiator, then disconnect the heater hoses from the core. Remove the screws or clips securing the heater core, replace it with the new unit, and reassemble the components in reverse order. Lastly, refill the coolant and check for leaks before starting the vehicle.