How do you change heater core 81 olds toronado?

To change the heater core in an '81 Oldsmobile Toronado, first, disconnect the negative battery cable and drain the coolant from the radiator. Remove the dashboard and the HVAC housing to access the heater core, which is typically located behind the firewall. Disconnect the heater core hoses from the engine compartment, remove the old heater core, and install the new one. Finally, reassemble the HVAC housing, reconnect the hoses, refill the coolant, and check for leaks.