Why is the heater core busted on my 1996 Cadillac Eldorado?

"brandon, here is what the service manual wants you to do :-):

""1. Disconnect the negative battery cable.

2. Partially drain the coolant. Refer to Cooling System Draining and Filling in Engine Cooling.

3. Remove the instrument panel compartment. Refer to Instrument Panel Storage Compartment Replacement in Instrument Panel, Gauges and Console.

4. Remove the right sound insulator. Refer to Instrument Panel Insulator Panel Replacement - Right Side in Instrument Panel, Gauges and Console.

5. Remove the heater and A/C programmer. Refer to Programmer Replacement .

6. Disconnect the driver air mix actuator (2).

7. Disconnect the passenger air mix actuator (3).

8. Remove the heater core cover.

9. Remove the inlet and outlet heater hoses from the heater core.

10. Remove the heater retaining screws.

11. Remove the heater core.""

Hope this helps, good luck."