How to Replace a Heater Core on an F-150 Ford Truck

Your F-150's heater will stop producing warm air if the heater core is no longer in good condition. Replacing the heater core requires removal of the dash board/instrument panel from the truck to access the core. You must also deal with the pressure of the air conditioning system. The process of removing and replacing the heater core might be different if you have an F-150 truck older than 1997.

Instructions

Preparation

1

Have the air conditioning system discharged; only a licensed technician at a Ford dealer's service department or auto air conditioning shop can do this.

2

Disconnect the battery, loosening the clamp nut and disconnecting the negative cable first, then the positive cable. Wait 2 minutes for the air bag power to run out.

3

Connect a hose 3/8-inch in diameter to the drain fitting on the radiator, unscrew the fitting and drain the engine coolant into a large container. Drain the remaining coolant at the engine block drain plugs.

Removal

4

Place the steering wheel in the lock position, then remove all the instrument panel trim bezels, removing their screws with a screwdriver and prying them off their clips.

5

Disconnect all the electrical connectors and ground cables behind the trim panels; the ground cables will likely require a wrench.

6

Unbolt and remove the passenger side air bag module, then unscrew and remove the pull handle and pillar trim panel on the door frame and the instrument cluster housing cover. Pry out the defroster grilles on the instrument panel with a trim stick.

7

Remove all the upper mounting bolts for the instrument panel with the wrench, and the screws within the defroster openings with the screwdriver. Detach all remaining electrical connectors on the instrument panel, then lift the panel toward the rear and remove it.

8

Disconnect the heater core tubes at the firewall within the engine compartment, squeezing their plastic tabs and pulling them off. Disconnect the evaporator lines, the main vacuum line and the plenum tube, then plug the heater and evaporator lines with rubber plugs.

9

Unscrew the bracket at the top of the heater core housing with a screwdriver, then unscrew and remove the heater core cover.

10

Pull out the blend-door assembly, then remove the heater core from the housing, making sure not to damage the foam seal within the case.

Installation

11

Install the heater core in the housing, making sure the foam material is correctly in place. Close the heater core cover with its screws and screw the bracket back onto the heater core.

12

Reconnect the vacuum line, plenum tube, evaporator lines and heater core tubes. Use new retainers and O-rings with the heater hoses when connecting them to the firewall.

13

Reinstall the instrument panel in the reverse order of removal, reconnecting the electrical connectors, mounting fasteners, defroster grilles and trim panels.

14

Refill the engine coolant at the radiator neck; inspect the old coolant's condition and use fresh water/antifreeze if the old mixture is contaminated.

15

Reconnect the battery, connecting the positive cable first, then the negative one.

16

Have the truck's air conditioning system recharged at a Ford dealer's service department or auto air conditioning shop.