Does anyone have a good set of instructions for replacing the rear heater core on a 99 expy ? The main thing I need to know is, does the AC system need to be discharged to replace the core ?

 

REMOVAL & INSTALLATION

1997-99F-250, F-350 and F-Super Duty models




Fig. Fig. 1 Heater core removal-1997-98 F-250, F-350 and F-Super Duty models


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

Disconnect the negative battery cable.
Drain and recycle the engine coolant.
Disconnect the coolant hoses at the heater core tubes.
Remove the glove compartment.
Position the Rear Anti-lock Brake System (RABS) module to the side.
From inside the passenger's compartment, remove the 7 screws that secure the heater core access cover to the plenum chamber.
Disconnect the vacuum source, but leave the vacuum harness connected to the cover and remove the cover.
Remove the heater core.To install:
Installation is the reverse of removal. Replace any damaged sealer.

F-150 and F-250




Fig. Fig. 2 Remove the A/C plenum demister screw and remove the A/C plenum demister adapter





Fig. Fig. 3 Disconnect the vacuum line





Fig. Fig. 4 Remove the heater core bracket





Fig. Fig. 5 Remove the 13 retaining screws and remove the plenum chamber top





Fig. Fig. 6 Remove the heater core


CAUTION
Never open, service or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. Also, when draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

Disconnect the battery.
Drain and recycle the engine coolant.
Remove the instrument panel. Refer to .
Compress the holding tabs and disconnect the heater water hoses at the heater core.
Remove the A/C plenum demister screw and remove the A/C plenum demister adapter.
Disconnect the vacuum line.
Remove the heater core bracket.
Remove the 13 retaining screws and remove the plenum chamber top.
Remove the blend door assembly from the case.
Remove the heater core.To install:
The installation is the reverse of the removal.

Expedition and Navigator




Fig. Fig. 7 Remove the A/C plenum demister screw and remove the A/C plenum demister adapter





Fig. Fig. 8 Disconnect the vacuum line





Fig. Fig. 9 Remove the heater core bracket





Fig. Fig. 10 Remove the 13 retaining screws and remove the plenum chamber top





Fig. Fig. 11 Remove the heater core

Disconnect the battery ground cable.
Drain and recycle the engine coolant.


CAUTION
Never open, service or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. Also, when draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

Remove the instrument panel. Refer to .
If equipped with the 5.4L 4V engine, remove the junction block splash shield.
If equipped with the 5.4L 4V engine, remove the bolts and disconnect the cable ends from the starter relay.
If equipped with the 5.4L 4V engine, remove the junction block bracket.
Disconnect the heater core hose couplings.
Remove the retaining screw and remove the A/C plenum demister adapter.
Disconnect the vacuum line from the A/C plenum demister adapter.
Remove the heater core bracket.
Remove the 13 plenum chamber top retaining screws.
Remove the plenum chamber top.
Remove the blend door assembly from the case.
Remove the heater core.To install:
The installation is the reverse of the removal.

1999-00 F-250SD, F-350 and F-Super Duty Models




Fig. Fig. 12 Remove the electronic blend door actuator and bracket assembly





Fig. Fig. 13 Remove the heater core cover screws and ...





Fig. Fig. 14 ... remove the cover





Fig. Fig. 15 Remove the heater core from the housing


CAUTION
Never open, service or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. Also, when draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

Drain and recycle the engine coolant.
Disconnect the heater water hoses from the heater core.
Disengage the stops and lower the glove compartment door.
Remove the electronic blend door actuator and bracket assembly.
WARNING
The heater core cover must be raised vertically before removal to avoid damage to the heater core housing.

Remove the heater core cover screws and remove the cover.
Remove the heater core from the housing.

To install:


WARNING
Position the temperature blend door manually to properly align the actuator and the door. Do not power the actuator electrically. If it is not engaged with the temperature blend door, damage to the actuator may occur.

Add gasket between housing and cover before installing cover.

The installation is the reverse of the removal.

Got this from autozone

 

Those directions are for a front core.

 

Never mind, figured it out myself. Pulled it all apart, put it all back together, it wasn't that bad to replace. Guess I should of took photos so I could write some instructions up.

 

Madsonp,

Did you end up having to open up the AC system in order to replace the rear heater core? Nobody did ever answer your question....

 

No, you don't have to open the AC system to do it.