How do you replace the heater core on a 1998 Buick Regal?

To replace the heater core on a 1998 Buick Regal, start by disconnecting the battery and draining the coolant from the radiator. Remove the dashboard and the center console to access the heater core, then disconnect the hoses and remove the mounting screws to take out the old core. Install the new heater core by reversing the disassembly steps, ensuring all connections are secure, and refill the coolant before reconnecting the battery. Finally, check for leaks and test the heating system to ensure proper operation.