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, rahter 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?
85 Heater Core=Cut Box To Replace
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rd
Founding Member
It would seem to be more trouble to get in there and cut and make a mess than it acutally is to just disassemble it and reassemble it. Done it twice, guess the third time is coming if the stop leak fails...... It is a 6 hour job, less with practice, I think, but so are lots of other things we do to the car.
Well, I could see that if the core box top / lid section had not already been rendered (broken, but cleanly...) where I could easily (well...) remove it and I had to remove everything above it, i.e. the dash, to access it. Fact is there isn't really anything in my way (in front reaching through the glove box oening)if I remove another section of the heater core box on the front to expose the rest of the heater core. Right now I can stick my hand on top of of the heater core and back in there a little way (didn't really try and see how far in I could reach, got interuppted and had to quit working on it for the night). I'm real interested in not having to remove the dash (working alone in driveway with no overhead cover and only a worklight to see by, plus who would really want to?). I wish I could get a picture of this as it sits now for you to see (but don't have the capability) so you could see the amount of access I seem to have. It may be that the core is too long to come out or go in smoothly this way (although it appears the guy that replaced it for me before did it similarly, and no I couldn't find him now if I had to), but right now it appears that there is room. What are the measurements for a stock replacement heater core for a 1985 Mustang with air?
Just posting to hopefully pop this back-up to the top for those logging in the evening. It seems there have been others cut it without problems, but there are no real specifics on their posts. I beleive it was on Turboford.com, or something like that. Anyway, if it's not raining this evening, I'll probably be taking the Dremel to it.
yellow5.0cobra
Founding Member
Those early style dashboards are VERY easy to take apart, its roughly about 5+hours for an amatuer.
ECU5.0
Banned
man, i replaced my heater core and i didnt have any problems. i dont even know anyone who has done it...so they were no help. it was hard...just a little time consuming. oh yeah, and after i got it all back together my heat worked for about a day...and now it doesnt get very hot, its hotter than the air outside...but nothing to warm you up. does anyone know anything about that?
trbkrb
Founding Member
Yes, you can try to cut it out, but one of the causes of new heater core failures is when you don't clean out all of the old dry sealant in the box, and the new core fins are damaged on it during the install. I did a half way cut job on mine, way before the articles on the internet (91 or so). No way was I going to discharge my AC for a heater core, so I removed the dash and ended up cutting a flap so I could get it out. First time took the better part of a day, second time about 4 hours. Hopefully this time, it will be less, since I've done it before. But I have a new dash to put in, so it will be worth it.
Good luck!
Good luck!
1986LX2002
Founding Member
- Aug 15, 2002
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I need to replace my core in my 86. And I was reading the my manual about how to replace it, step 1. "rip dash out lol" I was like you gotta be kidding!! I really need to do it, but since my car sat in a field for years the dash is really bad and cracks when i even try and take it apart. Are there any tips or tricks you guys have or know of or something i need to look out for?
85 Coupe 5.0
Founding Member
I've done it many times. Mainly because i've owned two 85's and one '86. It is a very simple job, even the firist time I did it. It all depends on the car. Some models of the Mustang came without factory air. If the car does not have factory air conditioning, then simply take the glove box door out and there will be an access cover to the heater core right behind the glove box. remove the 4 screws on the cover, disconnect the heater hoses and remove the core. Those of us WITH factory air, well, we got to remove the dash. I do not agree on cutting the heater box to do this, it's improper and not that much harder to just do the job right. UNLESS, you have a working A/C. THEN cutting that box would be a great idea, because if not you have to evacuate and recharge the A/C system. Other than the A/C thing, taking the dash completely out isn't that much harder. just my thoughts.
Don't be a butcher and do the job right. Otherwise you will be sorry. When you get the old core out, you will see it's enclosed by some type of insulating product. Either reuse it or use somethimg similar. It's to keep the core from moving around in the housing and eventually rubbing a hole in the new core. Pulling the dash is not as hard as it seems. Depending on your mechanical apptitude, you could have it done in three to six hours. (Or you could have a local shop do it for your.) Don't use RTV!! When it heats up, even after its dry, you may end up with an oder you can't get rid of.
Is this a big enough bone?
Is this a big enough bone?
rd
Founding Member
PRO50SC said:
Just to add that I have done it twice on my 79, and did not have to discharge the ac either time. With the dash out, and the box unbolted from the firewall, there is barely enough room to get the top cover off and change the core. No, I am not looking forward to doing it this time, but it will work again.
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?
Hmm, wonder how many purists just had the eyes roll back in their heads
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?
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.
). 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.
NO_RICE
Founding Member
There is a reason that repar manuals have pictures, I read your post and I really can't visualize most of the fabrication. It has been a while since I change my heater core though. I didn't think it was that bad, but it only took me about 6 hours.
Well, first of all, my repair manuals are typical of most, i.e. poor pictures. The main two I used were the Chilton's and the factory Ford service manual from 1985, which should be the best you can get. My initial reason for trying a different approach was to see if there was an easier way to do it. Just because 50,000 'Stang owners have done the same repair doesn't necessarily mean that they all did it the same way, and I am certain they have not all posted their experiences on the Internet. When I rebuilt my wife's 1994 Formula Firebird's LT-1 Optispark, every poster advised it either couldn't be done, advised against or encouraged the experiment in saving big $$$'s if it worked (what did they have to lose, it was my car, time, effort and money). Guess what, it worked and worked to the tune of approximately $1,000 in savings kept in my pocket and hopefully someone else was able to benefit from the postings (I had numerous e-mails for details on the repair, several of which decided not to even tackle any part of the repair as it is very involved).
If I had a quality digital camera, I would have taken pictures for folks that were interested in seeing this, but that just didn't happen. About the best I can do is direct you to this photo (hope this works):
http://images.cardomain.com/member_images/3/web31500-315999/315446_40_full.jpg
This shot (not mine) shows the box from side / head on, but you see the heater core box lid on the left nestled up to / under the metal framing of the cowl (correct terminology?). Mine was basically broken straight across the top (again, not by me, but by a guy who did this repair for me back in '96, and no I wasn't there to watch), and he cut it across the face (where the lid lip would rest) down about an inch. Now, I believe this was part of the problem I had with the thing for years losing fluid slowly and mysteriously and never finding a hose leak, before I ever smelled the anti-freeze or had the steam coming from the vents and occasional drop in the floorboard. He damaged the inlet / outlet end ever so slightly (can't see the warpage, but the discoloration from the fluids is concentrated on this end) by cramming it in there at too step an angle, plus he scraped the bottom veins in a couple of spots. I cut down an additional 3/4 of an inch and had plenty of access as described in the other part of my post to go pretty much straight in without too much of a tilted angle. Is this method for everyone? No, not if you are squeamish about cutting something on your car, although it really is minor, and you will never see it. It will allow you to forgo evacuating the A/C and dropping the blower / core / evaporator housing, so for me it worked great, mostly for the next time I had to replace the thing. All the time consuming modifications have been performed, so this will be a synch (relatively speaking, since I performed everything as a one man job and the reattaching of the dash is a little physical and awkward). I really don't believe it will take me more than 3 to 3.5 hours next time, depending on how difficult it is to remove the heater hoses, though by then it will be replacement time for them as well. Another note, I am by no means a professional mechanic, nor do I own pro quality tools (my small socket drive won't hold unto the sockets anymore, so you know that's frustrating, but it does work), I am just a poor guy who must do his own repairs and likes to do them the least painful / expensive way possible. I hope something in here will help someone else save themselves a load of time in the future.
If I had a quality digital camera, I would have taken pictures for folks that were interested in seeing this, but that just didn't happen. About the best I can do is direct you to this photo (hope this works):
http://images.cardomain.com/member_images/3/web31500-315999/315446_40_full.jpg
This shot (not mine) shows the box from side / head on, but you see the heater core box lid on the left nestled up to / under the metal framing of the cowl (correct terminology?). Mine was basically broken straight across the top (again, not by me, but by a guy who did this repair for me back in '96, and no I wasn't there to watch), and he cut it across the face (where the lid lip would rest) down about an inch. Now, I believe this was part of the problem I had with the thing for years losing fluid slowly and mysteriously and never finding a hose leak, before I ever smelled the anti-freeze or had the steam coming from the vents and occasional drop in the floorboard. He damaged the inlet / outlet end ever so slightly (can't see the warpage, but the discoloration from the fluids is concentrated on this end) by cramming it in there at too step an angle, plus he scraped the bottom veins in a couple of spots. I cut down an additional 3/4 of an inch and had plenty of access as described in the other part of my post to go pretty much straight in without too much of a tilted angle. Is this method for everyone? No, not if you are squeamish about cutting something on your car, although it really is minor, and you will never see it. It will allow you to forgo evacuating the A/C and dropping the blower / core / evaporator housing, so for me it worked great, mostly for the next time I had to replace the thing. All the time consuming modifications have been performed, so this will be a synch (relatively speaking, since I performed everything as a one man job and the reattaching of the dash is a little physical and awkward). I really don't believe it will take me more than 3 to 3.5 hours next time, depending on how difficult it is to remove the heater hoses, though by then it will be replacement time for them as well. Another note, I am by no means a professional mechanic, nor do I own pro quality tools (my small socket drive won't hold unto the sockets anymore, so you know that's frustrating, but it does work), I am just a poor guy who must do his own repairs and likes to do them the least painful / expensive way possible. I hope something in here will help someone else save themselves a load of time in the future.
