85 Heater Core=Cut Box To Replace?

[5spd85GT]

I have been all over the Internet and have seen no mention on simply cutting through the box surrounding the heater core to replace it, rather than remove the dash. I had the job done on my '85 GT many years ago (early 1996) by a guy who apparently did this method sort of half-way, i.e. there is a piece (approx. the width of the core and about 1.5 inches high) cut from the front of the box and apparently he loosened things up just enough to pry up the top cover (broke it actually on the back side and that was sealed with RTV along the seam) and slide the new one in, and then cover the hole with RTV. Well, this has had a slow leak for years (anti-freeze smell in car, film on windows, mysterious slowly disappearing fluid from radiator, and most recently fog out the vents) until this weekend when the anti-freeze is literally poring out the AC pee hole right onto the exhaust (yeah, not hard to find that leak)! I was able to remove the wonderfully located 5/16 screw at the top of the core cover and remove it (as I said, the guy had pried it up and broken it for removal years ago), so the question is, why not just cut down the front of the box the rest of the way to allow access to the old core and slide the new one in? Afterwards, a little J.B. weld and some more RTV to seal things up. It seems entirely too simple (versus taking out the entire dash), so who can give a little feedback to this idea?

[Dark_5.0]

Heater cores suck. I always heare people saying that you can get the core out other ways. When I did mine on my 88GT I had to remove the dash and it sucked really really bad.

Better you than me ..........J/k

[Fox Body]

Yeah, I heard about cutting the front out of the heater core box. I'd like to get that done in the '79. THat is just stupid that Ford made it that way. Pisses me off. I'd like to hear from someone who's done it successfully with no adverse effects and do mine like they did theirs. Or, I may just trade out A/C dash for a non-A/C dash where you can just go through the glove box to change the heater core like my first '79. I think that would be the wisest since I don't plan on using A/C on the car anyways, but I do want my heat.

[Maroon 5.0 LX]

Why not get a shop manual and do it the right way by removing the dash? May take a little longer, but it will be done right, and not butchered up like some novice did it.

[5spd85GT]

Oh, I have plenty of manuals, including a Ford service manual, that's why I want to cut the stupid thing out. I went ahead and started work on the cutting last night. Only glitch I've run into so far is that the box front is double walled (hmm, what are the odds something like this would happen while working on a Ford?). At first I thought I had cleanly cut through, then I realized I had a whole other wall to cut through (and yes, I realize it is probably an insulating property). Would have finished that too, but the battery pooped on the Dremel. Hell, I had more trouble getting the larger of the two heater hoses off under the hood than I have had inside the car so far.
As far as butchering, I do not consider anything butchered if a repair is completed and the function is restored without molesting something cosmetic that matters (the heater core box "cosmetics" do not matter unless you are standing on your head in the passenger side floorboard, and if it is working properly, who cares?). If Ford had designed this component with half a brain (you know they didn't, be honest) they would have included an access door on the front of the core box for A/C equipped cars (Gee, how simple would that have been?). Off topic, but another example: changing the plugs on a stock '85 5.0 with all the smog crap routed as it was (I say was, 'cause on mine, it ain't no mo'). I peeled many a layer of skin off getting those rear plugs changed back in the day, and now, well, it's almost pleasant.
Okay, enough ranting. I appreciate everyone's view points on this topic. Where would the fun be if we all took the same approach and thought just alike, right?
I will post again, hopefully tomorrow as the job progresses or if I discover anything else helpful in the procedure.

[Maroon 5.0 LX]

Well, you didn't like my first suggestion, but consider this one with more vigor...

Don't install a GDI (Go Dan Industries) heater core. They are sold by Auto Zone and many other places.

[5spd85GT]

Thanks, I usually only go to Autozone out of dire desparation. I forget what the one is that I picked up at O'Reilly's, but it does carry lifetime warranty (for what that's worth on a $20 part). Still looking for suggestions on what to seat the core with in the box for cushion / whatever.

[Fox Body]

Hmm. Thanks for taking this on (something I've not wanted to screw with in the past). I am curious to hear the results.

[82 GT]

This is a good thread!! I'm curious too as to how this experiment works out for you. If it works, then maybe you might want to post a tech article explaining how it was done............maybe some pictures as you go??

[5spd85GT]

Okay campers, just a small update. Only had a short time to work on it last night,and...ran into a snag. I was able to remove the remaining material that will allow the core to slide up and out freely, but I miscalcualted the room / clearance (i.e. length) to pivot the core out. Okay, the A/C vent ducting is in the way and cannot be pushed upward enough to allow clearance. It is slight on the left (facing the dash) and a little more significant on the right. This is blocking the upper most corners of the core. Obviously (or maybe not so), there is no easy way to loosen anything to allow clearance (where is it going to go, no room). I am noodling with this and hate to say it again, but one could cut the sections of ducting with a Dremel disk to clear the core and then seal them back with ducting tape, or something similar. I'm talking about cutting a section to provide clearance, not cut the duct in two. Looks as if the right hand cut would be diamond shape (especially if it were laid flat) and the left would be similar, but much smaller. Ideally, this would also allow for a quick (well...) change when this needs to be done again (you all know it will).
Hmm, wonder how many purists just had the eyes roll back in their heads?
What's that? Yes, it is possible that I would already have finished the job by doing it the looooonnngggg way. Doubt it though. We have rain in the forecast for the next few days, so I probably won't be able to get back on it until Sunday.
I did notice (with my fingers) the spongy foam underneath the core (saturated in fluid), but without being able to stick a mirror in there to look around, I'm not sure about where the factory placed their seating goop for the core. Anybody, anybody?

[Dark_5.0]

Man ................It took me a very long day to change out mine and yes it sucked.

But one day and I didnt butcher anything

Good luck though........lots of people have tried and tried but far as I know removing the dash is the way to go.

[Maroon 5.0 LX]

This may help, I haven't tried it.
http://home.netcom.com/~skent/mustan...ore/hcore.html

[Fox Body]

Originally posted by 5spd85GT
...Ideally, this would also allow for a quick (well...) change when this needs to be done again (you all know it will).
Hmm, wonder how many purists just had the eyes roll back in their heads?
What's that? Yes, it is possible that I would already have finished the job by doing it the looooonnngggg way. Doubt it though.

LOL

Man, if you were a nearby friend, I'd come out there and try to help you. 2 heads are always better than one. Would you be able to post any current pics of the area you're working on? Maybe we could throw out some ideas. I am still interested in the outcome of this..... Sorry I can't be of more help.

[5spd85GT]

I appreciate the generosity of your response. Most folks (read: my 80 yr. old dad, but that's a long story with a lot of history beginning with my late brother's '69 coupe many, many years ago...) hear you're even touching a 302 equipped Ford and cringe a little and sort of start backing away slowly, disengaging themselves with as much dignity as haste will allow. Okay, but seriously, my only friend with this sort of weird bent for Fox body 5.0 punishment has an '89 LX 5.0 (he ordered new) that has had, mmm, I'd say 5 or 6 engine configurations over the last few years (latest, but currently torn back down being, I believe, a Motorsport 351 with twin turbo that was running mid 10's on pump gas), but his shop and repair calendar are understandably full.
I believe I will finish this fairly quickly (ha, ha, ha, ha, whew... eheh) Sunday if the weather clears by then, and I am going to attempt to take some digital pics; however, the camera (i.e. cheap) is not good at all with close ups, so no guarantees. I actually have not been trying to rush (much) through this project, so the difference in time between the "manual" and this method I beleive is irrelevant at this point. If (yes purists, I said if), this method proves to be viable, I would not estimate it taking longer than the "manual" method the first time and it will take far less time to do again when necessary.

[82 GT]

Well....come on...let's get a move on!!! I have 2 mustangs here that need heater cores. I wanna see if your experiment works before I go cutting up A/C vents and crap........

[5spd85GT]

Mmm, mmmhmmm. I reckon I could tinker 'round with it a little more and whatnot, mmm. Ite then.

[HiFlow5 0]

Come on guys, heater cores aren't that bad. It just takes a little time and patience. I just replaced the heater core in my 89 a few months ago. Here's a link to where I have detailed photos and steps on replacing. Although, an 85 might be slightly different, but you still might find something here useful.
www.cardomain.com/memberpage/315446/6

-Craig

[5spd85GT]

No, I didn't die, I've just been very tied up lately, soooo here is the rest of the story. Once I had an afternoon break from the monsoon season where I could get back to the car, I decided not to cut anything else and see if I could drop the dash enough to access the heater core through the amount of opening I had i.e. the piece that was already broken / cut from when the guy did this for me years ago and the amount I had removed below this. Long story short, I still hate whomever engineered this set-up, but now I dislike the manual-writing guys also. This is not a 7-8 hour repair (as the chorus in the background says "I told you so"). If you are in any form or fashion mechanically inclined and know how to improvise your tools (or just already have the perfect ones to fit everything) then you can remove the console and drop the dash in, oh, maybe an hour without rushing too much. I did use a pair of vise grips and a (trying to remember) 9/32 small socket to remove the dash top screws, between the glass and the dash top (and yes that little one in the middle can hold up the entire dash ). Oh, and have that stub Phillips head screwdriver handy as well. The other funky bolt would be the one you access after dropping the steering column. My manual was a little vague there, and I didn't see it the first evening in the dying light, but found it far back in there the next day (10 mm deep socket with extension helps).
Now, here is where my repair did go much more quickly than others: because I could access the heater core with some of the front of the box housing removed and about half the lid (up to just before it tucks under windshield surround area) removed, I could hold the dash down and slide the old heater core out very easily. It is not necessary to drop the heater / evaporator unit (with all the ensuing issues), just bite the bullet and cut or break the stupid box lid and save precious moments of your life for more worthwhile pursuits...really, no one will ever see this and if they do, they are changing the heater core and will thank you later. Now, to install the new one I ran into a couple of learning curves: the "sticky tape" (looks like a tar fruit roll-up with roofing shingle specks in it) I used to line the heater core box housing to rest / cushion the new core on likes to stick to your fingers instead of the box (plastic, go figure), so leave the white tape paper on and apply pressure along this. Also, I used a razor to cut it into thin strips to fit the box dimensions. The core; however, grabbed unto the strip I put on the passenger side bottom and proceeded to ball-up, obviously sticking the core right there. I just left that side off and it slid into position up to the firewall opening. Great...except I had left the little rubber protective end caps on the new core and they will not go through the opening. Third times the charm, and it slid right through and seated perfectly. Also, the heater flapper door control arm needs to be held down to keep it from ripping a hole in the bottom of your new core. I simply pushed it down and tied a string around the end and tied the other end off to the brace on the front of the assembly. I cut a piece of flat, black heavy plastic that came off of who knows what that my dad had made into an ice scraper (or maybe it already was one?) out in his garage and rat tail filed this to fit in the hole the guy left when he replace the core years ago. Yes, there were still some little gaps, but these filled in easily when I siliconed the piece I cut off the front and the lid top back onto the housing. Yes, it had (umm, still has just faintly when you first activate the fan) a little silicone odor for a few days, but that’s a heck of an improvement over the anti-freeze stink (silicone = the sweet smell of success ).
On the firewall side (under the hood) I had to come up with something to block the hole off (removed most of the old silicone blob in the removal of the old core). I cut a piece of black plastic flower bed edging (the flexible stuff that comes in 20 foot rolls) to fit the opening and cut two holes in this to fit the inlet / outlet necks through. I built up a good surrounding of black silicone (filling up the area pretty much), and then put the plastic piece (after the silicone had cured about ten minutes) on which even gave it a very finished off look, and sealed up nicely.
In all actuality, the two single items that took me the longest were: disconnecting the heater core lines under the hood (man were they ever on there!), and, embarrassingly enough, getting the stupid glove box back on to my satisfaction. Apparently, as I was removing things, I didn’t notice a minute difference in these two screws (first two I removed on the whole repair, last two to go back on) and I had heck getting the two screws I had left (that’s right, no left overs) to fit (a hair to large). I found one of them holding the dash pad on, but just made the other one work, but still it was just stupid how I couldn’t get the thing shut the way I wanted.
Are you still awake? Figured most folks would have quit reading long before this, hope not though as I feel the couple of tips I have imparted here will help someone. Now, when I have to replace this heater core (it’s a Ford folks, you know I will…well that and I‘ll never sell her…) I should be able to do it in record time because I can easily take the lid and front off my heater core box for easy access.

[Fox Body]

Hey man,

thanks for taking the time to write all that. I read it all-- interesting and entertaining. But, after reading it all, can't seem to remember the key points. ... Basically, you cut a part of the front of the heater core box and just broke off the top?... Could you like just write the few key points about the modification of the heater core box, without all the story. Like 1), 2), 3).

[82 GT]

I don't which took longer. The time it took you to repair your heater core or type that novel.
For awhile there, I thought I was reading WAR AND PEACE .