How do you change a heater core on a 1998 Ford F150?

There is no short cut or fast way to do this. The dash has to come out to access the heater box and replace the core. So the steps in replacing the heater core are to disconnect the heater hoses, remove the dash, to access the heater core cover on the front of the heater case and replace the core. Reassembly is in the reverse order as disassembly. Fill the cooling system with new coolant, and burp the air form the cooling system.