1992 Mustang LX Heater Core Issue

TownCarTechi · 4 Weeks Ago

Hi, I have a heater core problem with a 92 Mustang LX 2.3L. I originally posted in the 5.0L section by mistake. I've searched on the forum and found two posts that gave very detailed instructions for dismantling the dash. I've been successful in getting through all of those instructions (thank you so much, members), but now I can't go any further without some advice.

I have some pictures to show my problem. I can't pull the heater box out far enough to get to the last back screw because the AC dryer is hitting against the firewall.

The 1st picture is the heater box. The last screw is on the left side in the back underneath the dash.

The AC hasn't worked for awhile so I don't know if there is any refrigerant in the system, so I'm unsure about the hazards of removing the AC dryer completely. The 2nd picture shows the AC dryer against the firewall. I can remove the top nut if it is okay, but I've never removed the type of special connection on the bottom.

I did remove the bolt that held the metal frame up on the passenger side, but should I also remove the bolt that holds up the metal frame on the driver side? I'm concerned what else may come down if I do so, including any electrical connections or wires that may be stressed.

This 3rd picture is from the driver side and you can see the bolt in the far left of the picture that holds this part of the frame in place.

I'm happy I've come this far because this is my 1st experience with heater cores. But I'm also unhappy if I can't overcome this last hurdle.

Thanks in advance for your help.

mg man 75 · 4 Weeks Ago

I would take it to a ac service shop and make sure no freon. It is illegal for you to vent it. If no freon you can dismantle and reassemble and if desired take back to them to recharge.

TownCarTechi · 3 Weeks Ago

Thanks mg man, I did have a pressure gauge on an EZ Chill bottle of R134a that I purchase at WalMart several months ago. I checked the low pressure side and had no reading so I decided to undo the top connection, and there was no release. Now I need to get a 1/2" line connection tool to undo the compression fitting. It's possible that the maintenance guys at my job may have one, otherwise I'll need to purchase. Once that fitting is undone, I'm confident I can finish the job.

One other question is about the heater box lid. I've read that there might be caulking around the lid to help seal against air leaks or there may simply be a foam seal. Any comments?

DBT4220 · 3 Weeks Ago

the last heater box i took apart in a Stang. (my parts car) has a black goo sealant around the underside of the lid.

TownCarTechi · 2 Weeks Ago

Hi members, finished up the replacement of the heater core and had the cooling system flushed yesterday. I plan to hook up the pipes tonight. In the process of putting everything back together, I ended up with one large black piece that doesn't have a home. I took pictures of the top and bottom views of the piece in hopes that someone could tell me what I missed during the reinstallation.

I took a picture of the steering console to show the rubber gasket that is hanging out, but I realize now that the steering wheel cover goes over the gauge cluster binnacle and not underneath it. I'll correct that tonight, but I wonder if my extra black piece also goes somewhere underneath the steering wheel.

Thanks so much for your help and comments.

mg man 75 · 2 Weeks Ago

Yes Metal piece goes under steering column under the plastic cover. Not sure what is for. I think a antidive to prevent someone from going under column in a crash. I assume. Maurice

p_books · 2 Weeks Ago

Remember years ago when I changed a heater core on my 80 mustang. Took apart the whole dash (the instructions hinted that I only had to take out the glove compartment - Yeah, Right!)
Did the whole thing and the new core immediately leaked inside a week.

Learned my lesson and took a cutting tool and took out the heater core through the firewall from the engine compartment side. Little 4 banger left plenty of room for this and the old heater core showed me where to cut.

True definition of PDQ second time around

TownCarTechi · 2 Weeks Ago

Thanks again, Maurice. I see how the black piece fits nicely into the plastic cover that goes underneath the steering wheel. But I still can't figure out how to move the steering wheel cover over the gauge cluster binnacle. It surely must go over and not under, because if I leave it under, it stresses the binnacle as I tighten the nuts that hold up the steering wheel. I tried to loosen the binnacle and then raise the steering wheel into position, but that doesn't seem to work. ??? Help!