How do you replace heater core in 1993 mercury grand marquis?

To replace the heater core in a 1993 Mercury Grand Marquis, first, disconnect the battery and drain the cooling system. Remove the dashboard and the center console to access the heater core housing. Disconnect the heater core hoses from the engine bay, unbolt the heater core from its housing, and then replace it with the new one. Reassemble the components in reverse order, refill the cooling system, and check for leaks.