Published on 2013-11-04
The heater cores in Fox Body Mustangs are infamous for leaking and causing poor performance of your heating system. We get a constant bararage of questions on how to replace 79-93 Mustang heater cores. We listened to the outcries from our fellow enthusiast and we created a step-by-step walkthrough video on how to replace your heater core. The installation does require you to have roughly a half to full day of time set aside to tackle the job; however, doing the job yourself can save you hundreds of dollars!!!
A bad or leaky heater core can cause steamed up windshields, strong coolant smell coming from the dash or even worse -- wet passenger side floor. Don't let a bad heater core ruin you carpet and cause you to drive around in the cold! Pick up a 5.0Resto replacement heater core today and watch our installation video! We have them available for both A/C and Non A/C Mustangs.
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As you can imagine, latemodelrestoration.com employees have varying levels of projects going on in their spare time. And this one quite literally just came out of the weeds. It does run in drive now, but it is in dire need of a heater core, and we know you've been begging for that install video, so we're going to give it to you. As with any installation, you'll want to start by disconnecting your battery and with this, you need to remove your seats in your center console. You can check out our console and seat removal videos to show you exactly how to do those steps.
Now, let's get on with pulling the dash. Remove the four bolts that retain the lower dash cross brace and then remove the brace. Loosen the front scuff plate screw. Remove the kick panel pushpin, and remove the cake panel. Do the same on the other side. Pull out the cluster of wires on the passenger's side, and separate all the connectors.
Remove the two nuts that hold the hood release cable bracket to the steering column and then let the cable and bracket hang free. Loosen the two nuts closest to you on the steering column, and then remove the two nuts near the firewall completely. Unplug the airbag, cruise, keyboarding, and ignition switch connectors. Support the column and remove the two nuts closest to you keeping the columns supported lower enough to unplug the three multifunction switch connectors. You can now allow the column to hang freely.
Remove the top two cluster trim bezel screws. Remove the bottom right cluster bezel screw. Using a small screwdriver, release the retaining tabs on the headlight and hazard switches. Remove this switches from the bezel and unplug all the connectors. You can then remove the trim bezel.
Remove the four cluster retaining screws. Disconnect the left-hand cluster connector. Disconnect the speedometer cable by pressing down on the plastic sleeve and then sliding it off the speedo housing. Disconnect the right-hand cluster connector and remove the cluster from the car. Loosen the single nut retaining the dash frame to the pedal assembly. You do not need to fully remove this nut.
Remove the speaker grill retaining screw in the speaker grill on both sides. Remove the two glove box door screws and remove the glove box. Remove the defrost vent trim. Remove the five screws along the top of the dash. Remove the single bolt at each lower corner of the dash at the kick panel area and then carefully lower the dash.
Unplug the blower motor, vacuum connections, and blower resistor along with the radio amp if equipped. Over by the pedal assembly, unplug the brake switch connector. Rotate the dash out of the way carefully. Remove the single both at the base of the HVAC box. Loosen the two bolts on the HVAC box upper brackets. Remove your heater hoses at this point if they're still connected. Our were already bypassed.
Remove the two nuts that retain the accumulator bracket to the firewall. Loosen the accumulator bracket screw and slide the bracket all the way down the accumulator. Remove the two large diameter nuts retaining the HVAC box to the firewall. Disconnect the vacuum line. Back inside, fully remove the two upper bracket bolts you loosened earlier and pull the HVAC boxes far in as possible. This will expose the heater core cover lid.
Remove the two cover screws closest to you. Taking your time, trust me you'll need it, remove the two cover screws near the firewall. Lift up the cover and remove the heater core. This is where it was leaking at. Take your new heater core and wrap it with the supplied foam tape. Slide the new heater core into the HVAC box, and reinstall the cover lid and four screws. Believe me it's not any easier than taking them out.
With the HVAC box back in place, you can reconnect your heater hoses and tighten down the clamps. Be sure to check and top off your coolant level. Reverse the removal procedure of the HVAC box. To hang the dash, line up the locating tab in the center of the dash with the hole in the firewall and the single nut you loosened but didn't remove with the slot on the pedal assembly. With the dash back in place, reverse the removal steps for the dash.
You'll notice we completed this job without taking lose anything with the AC. Now, if you were to go and have your AC system evacuated, you could disconnect the accumulator and your liquid line from the evaporator and pull the box completely out giving yourself a little bit more room to work. Couple of other things, you're going to want to have a drain pan to catch any coolant and after you hook you heater hoses back up to your new heater core, you want to check your engine coolant and top it off.
Please feel free to leave a comment if this video was helpful for you, and if there's any other videos and you'd like to see from latemodelrestoration.com.