New Heater Core
10-22-02, 06:36 PM
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New Heater Core
Arrrghhh.... I have to put a new heater core in my car... and soon! 
I'm going to do it myself (everybody else wants like a grand to do it... definitely don't have that kind of $$ lying around!).... any suggestions/help/expertise you'd be willing to share? I really apprecitate it... it'll be my first time doing something this "big" on a car, but as an engineer I think I can handle it. 
Also, if you know where best to get the actual core itself, that's be great too... I'm still looking for a decent price on one. Mazmart here in Atlanta sells used ones for $75, but for all the trouble they are to put in I'd rather not risk that one going on me in the next three years, ya know?
Peace, and thanks!
I'm going to do it myself (everybody else wants like a grand to do it... definitely don't have that kind of $$ lying around!).... any suggestions/help/expertise you'd be willing to share? I really apprecitate it... it'll be my first time doing something this "big" on a car, but as an engineer I think I can handle it. Also, if you know where best to get the actual core itself, that's be great too... I'm still looking for a decent price on one. Mazmart here in Atlanta sells used ones for $75, but for all the trouble they are to put in I'd rather not risk that one going on me in the next three years, ya know?Peace, and thanks!
10-22-02, 07:07 PM
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It's really not that difficult. The hardest part for me was disconnecting the hoses. I ended up cutting them with a kitchen knife. The worst part is laying on your back, with little space, your head is laying on your pedals, and there is no room to move you hands.
I actually replace the valve not the heater core but I did remove it and test to make sure it wasn't leaking. All in all it took about an entire Saturday. (thats with breaks and many beers.) you'll need them to dull the pain of standing up.
Are you planning on removing the entire dash or just go up under the dash? I recommend NOT removing the dash, it's a lot of work to get to the heater core that way. Good luck!
BTW: Are you positive it's the heater core? I thought that was my problem but it turned out to be the valve instead. It's right next to the heater core. I'd suggest, removeing the core and checking it before you buy.
Steven
I actually replace the valve not the heater core but I did remove it and test to make sure it wasn't leaking. All in all it took about an entire Saturday. (thats with breaks and many beers.) you'll need them to dull the pain of standing up.
Are you planning on removing the entire dash or just go up under the dash? I recommend NOT removing the dash, it's a lot of work to get to the heater core that way. Good luck!
BTW: Are you positive it's the heater core? I thought that was my problem but it turned out to be the valve instead. It's right next to the heater core. I'd suggest, removeing the core and checking it before you buy.
Steven
Last edited by Matlock; 10-22-02 at 07:12 PM.
10-22-02, 08:43 PM
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Well... in this case I'm certain it's the heater core 'cause it was leaking before the guy who owned the car before me completely disconnected the radiator hoses that flow to the heater. So I've got two blocked off hoses in the engine bay, and two open holes going through the firewall... and supposedly if I connect them back together bad things happen until I replace the heater core. Hell... for the trouble it it, I probably would want to replace the core anyway when I get the dash off...
How do you do it w/o removing the dash? I thought that was the only way?? I'm interested now... and where's the valve you mention? Might as well check that too... good call!!
How do you do it w/o removing the dash? I thought that was the only way?? I'm interested now... and where's the valve you mention? Might as well check that too... good call!!
10-22-02, 08:54 PM
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If you go out to your car on the drivers side get right up under the dash (by the pedals and look towards the center. There you should see both the heater core and the valve. The heater core is kind of hard to see but follow the hoses.
Not sure of your size, but I'm 5'8" and medium build. I was able to replace the valve and remove the heater core without removeing the dash. I did however remove a few heater ducts (little plastic things).
If you are replacing the core I would also replace the valve. It can be purchased from mazda. I wouldn't take the guys word for it, I would test the core once its removed.
I used a garden hose and tryed to build pressure in the core. If you don't see any leaks, its the valve.
You cant miss the valve it's brass and....well there are hoses going to and from it. Can't miss it. Hope some of this helps. I will try to help you out as much as I can, and more than likely you can do it without removeing the dash.
Steven
Not sure of your size, but I'm 5'8" and medium build. I was able to replace the valve and remove the heater core without removeing the dash. I did however remove a few heater ducts (little plastic things).
If you are replacing the core I would also replace the valve. It can be purchased from mazda. I wouldn't take the guys word for it, I would test the core once its removed.
I used a garden hose and tryed to build pressure in the core. If you don't see any leaks, its the valve.
You cant miss the valve it's brass and....well there are hoses going to and from it. Can't miss it. Hope some of this helps. I will try to help you out as much as I can, and more than likely you can do it without removeing the dash.
Steven
10-22-02, 09:13 PM
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Wow thanks for the info... I'll try it this weekend, if possible. Where would you get a core from, and how much do you think it'd be? I've tried to find them for less than $200... I found one once but I can't find the place again... grrr!
I'll let you know how things go getting it out...
I'll let you know how things go getting it out...
10-22-02, 10:06 PM
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If I was going to buy one it would probably be from CRAP or Schucks. I am note sure what stores you have around you though. Schucks wanted ~$80. Glad I can help, I know this stuff is pain. (especially while laying on your back for two hours) haahah
10-22-02, 10:16 PM
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I can help you, DS, since I just finished this project *today*.
The "best" and most "thourough" job would be to pull the center console, then the dash and its wiring and ventilation, and then to pull those hoses out of the firewall and pull the heater assembly. You would disassemble the heater assembly, swap in the new core, put new hoses in and call it that.
Your solution? Well, I guess I will walk you through both ways.
Matlock has a decent plan, and if you can swing it, then by all means do it. It might be easier on your shoulders and neck to pull the steering wheel (no big deal) before diving down under your dash to do this. But it's clausterphobic down there while trying this, and I doubt the Haynes manual or anything will walk you through that way as the way to pull the core. But basically, once all the piping is disconnected and the actuator is slid out of the way (the heater will have to be set to a certain option to swing the door one way or the other to move the actuator out of the way of the core--don't know what this option is cuz I did it manually when I was working on the core), the core slides out with some difficulty, like a cartridge. It might not really want to come out this way, but you can pull it real hard, a new one will most definitately slide in pretty easy with a tap. There are these U shaped grooves for the piping that only go a certain way, so the core will only go a certain way as well--you can't accidently face it the wrong direction or something.
Matlock's definitely right about replacing that valve if you can. I'm asking him how to do it right now.
Now for the long way. I don't know if you're going to want to try this or not, but I'll give you the lowdown so you can decide what you're getting yourself into here. (Note: After doing all the work in the below paragraph, you might find it worth your effort to clean just about everything, take the ducts and clean them in your kitchen sink with Ajax, and tidy up your carpet, or replace your carpet if its old) But here goes. Let's say the first step is to take out the center console... this comes out really easily by popping out the switch panel and undoing the screws exposed down there towards the front of the console, then lift up the armrest and unscrew the screws in there. WHen you undo the forward screws, you also undo some of the screws holding the dash in. If you look towards the front of the center part of the dashboard, down near where your feet go on both sides of the car, there are two diamond shaped panels of plastic held in with a clip and a single screw. Removing those will reveal two bolts for both sides of the bottom part of the dash. Then remove your stereo, that's pretty easy and covered all over the forum if you search for it. Then behind the two vent panels leading to each door (these things remove with a screw and a clip) there are two bolts on both sides of the dash that remove easily with a socket extention. Now, go up to the defroster panel. In the center there is a rectangular trim piece. This pops out (be careful, as the sunlight over the years makes this stuff brittle) to reveal a single nut. Undo that, and then the defrost panel removes with some popping of about four clips along its length. Set that aside and you'll see three more bolts for the dashboard along the top. Go down to the hood release for the car. Pull it so that the hood pops. Now get a wrench and unbolt the release, so that it slides off the dashboard assembly and just sort of hangs there. Removing that, your dash is only held on by wiring harnesses. Remove your steering wheel. Now remove the instrument cluster. There are about five screws for that, from the bottom of the dash, and from the inside bottom of the "ceiling" of the gauge cluster. Then pull it forward and unclip the wiring from where all the different instruments out. Set that aside and pull at the gauge pod. Angle it to the right and you should be able to slide your left hand in to undo the three clips for the gauges. One's for the four little gauges, one's for the tach, and the last one is for the speedo. Then pull out the gauge pod. If you want, now you can remove your shift ****. You *will* have to remove your shift boot, though. However, that is very easily done with some clip popping. Pull the dash up and back, it will stretch at the wiring harness clips. There are really only four wiring clips to work with. They're all blue and white, and it would be worth your while to mark these with masking tape and number them. These things easily come apart from each other with a clip of your thumb. Pull the dashboard out of the car (It's really light!) and then you'll see the white heater assembly sitting over the center of the cabin, and the blower motor off to the right. They're bridged by some heavy ventalation ducts (which are black) and those will have to be disconnected, which is done easily by popping out a plastic tab and then sliding the ducts off the assembly. The heater assembly is held on with three bolts, which are very easy to spot (two at the top, and the third on the bottom lefthand corner). Now you're going to open your hood. Drain your cooling system. Or you can just pull these hoses and let the antifreeze drain out of them. The two heater hoses (which I understand you don't have, but for prosperity's sake, we'll talk about them) come in by two holes about a foot apart towards the top and center of the firewall. You'll see them clamped onto something in the firewall itself, and they'll be the only actual two hoses that come through the firewall. Undo the clamps. Likeliness is that this has never been done before, so you're going to have to cut the hoses with a razor and unpeel them. Get new heater hose from the autostore and eight clamps. Marvel at the advancement clamp technology has had since the late eighties. Now you're going to pull back on the heater assembly and it's going to come right off, very easily. Take the heater assembly to a clean, flat place where its pieces are not going to get wet or lost. There are a set of metal clip fasteners that go around the housing that hold the two halves together. These things pop off with a flathead. Don't let them go flying off anywhere when they do, either. These two halves come apart, and when they do, the doorflaps that move about to open or close various ducts come loose and will be hard to reallign. You'll see the heater core, since hopefully you already have its replacement and know what it looks like (By the way, in Chicago, $75 is an unheard of, fantasic price for an RX-7 heater core--don't buy them used. You'll wind up having to do this job again if you do.) pull it after disconnecting it's hoses. Since you already bought the heater hose, cut about four inches off to replace the two pieces of hosing with. Pull out the old core and toss it. I suggest that you take this opportunity to clean the heater assembly and core chamber as best you can. Put the new core in, change the valve, and reconnect the piping and the hoses and ditch that stupid two wire clamp that Mazda used and use new clamps instead. That should use up half of your clamps. Now put your heater assembly back together, reverse of how you did it. Make sure the flap doors and everything align correctly and maybe disconnect some actuator arms to see if the doors move all right on their own. Reconnect the arms. Now put the assembly back in your car and hook up the new heater hose to the heater core pipes sticking out of the firewall. Now you can go backwards with these instructions to put everything back. And that's why this project costs a thousand dollars for a shop to do. :P
The "best" and most "thourough" job would be to pull the center console, then the dash and its wiring and ventilation, and then to pull those hoses out of the firewall and pull the heater assembly. You would disassemble the heater assembly, swap in the new core, put new hoses in and call it that.
Your solution? Well, I guess I will walk you through both ways.
Matlock has a decent plan, and if you can swing it, then by all means do it. It might be easier on your shoulders and neck to pull the steering wheel (no big deal) before diving down under your dash to do this. But it's clausterphobic down there while trying this, and I doubt the Haynes manual or anything will walk you through that way as the way to pull the core. But basically, once all the piping is disconnected and the actuator is slid out of the way (the heater will have to be set to a certain option to swing the door one way or the other to move the actuator out of the way of the core--don't know what this option is cuz I did it manually when I was working on the core), the core slides out with some difficulty, like a cartridge. It might not really want to come out this way, but you can pull it real hard, a new one will most definitately slide in pretty easy with a tap. There are these U shaped grooves for the piping that only go a certain way, so the core will only go a certain way as well--you can't accidently face it the wrong direction or something.
Matlock's definitely right about replacing that valve if you can. I'm asking him how to do it right now.
Now for the long way. I don't know if you're going to want to try this or not, but I'll give you the lowdown so you can decide what you're getting yourself into here. (Note: After doing all the work in the below paragraph, you might find it worth your effort to clean just about everything, take the ducts and clean them in your kitchen sink with Ajax, and tidy up your carpet, or replace your carpet if its old) But here goes. Let's say the first step is to take out the center console... this comes out really easily by popping out the switch panel and undoing the screws exposed down there towards the front of the console, then lift up the armrest and unscrew the screws in there. WHen you undo the forward screws, you also undo some of the screws holding the dash in. If you look towards the front of the center part of the dashboard, down near where your feet go on both sides of the car, there are two diamond shaped panels of plastic held in with a clip and a single screw. Removing those will reveal two bolts for both sides of the bottom part of the dash. Then remove your stereo, that's pretty easy and covered all over the forum if you search for it. Then behind the two vent panels leading to each door (these things remove with a screw and a clip) there are two bolts on both sides of the dash that remove easily with a socket extention. Now, go up to the defroster panel. In the center there is a rectangular trim piece. This pops out (be careful, as the sunlight over the years makes this stuff brittle) to reveal a single nut. Undo that, and then the defrost panel removes with some popping of about four clips along its length. Set that aside and you'll see three more bolts for the dashboard along the top. Go down to the hood release for the car. Pull it so that the hood pops. Now get a wrench and unbolt the release, so that it slides off the dashboard assembly and just sort of hangs there. Removing that, your dash is only held on by wiring harnesses. Remove your steering wheel. Now remove the instrument cluster. There are about five screws for that, from the bottom of the dash, and from the inside bottom of the "ceiling" of the gauge cluster. Then pull it forward and unclip the wiring from where all the different instruments out. Set that aside and pull at the gauge pod. Angle it to the right and you should be able to slide your left hand in to undo the three clips for the gauges. One's for the four little gauges, one's for the tach, and the last one is for the speedo. Then pull out the gauge pod. If you want, now you can remove your shift ****. You *will* have to remove your shift boot, though. However, that is very easily done with some clip popping. Pull the dash up and back, it will stretch at the wiring harness clips. There are really only four wiring clips to work with. They're all blue and white, and it would be worth your while to mark these with masking tape and number them. These things easily come apart from each other with a clip of your thumb. Pull the dashboard out of the car (It's really light!) and then you'll see the white heater assembly sitting over the center of the cabin, and the blower motor off to the right. They're bridged by some heavy ventalation ducts (which are black) and those will have to be disconnected, which is done easily by popping out a plastic tab and then sliding the ducts off the assembly. The heater assembly is held on with three bolts, which are very easy to spot (two at the top, and the third on the bottom lefthand corner). Now you're going to open your hood. Drain your cooling system. Or you can just pull these hoses and let the antifreeze drain out of them. The two heater hoses (which I understand you don't have, but for prosperity's sake, we'll talk about them) come in by two holes about a foot apart towards the top and center of the firewall. You'll see them clamped onto something in the firewall itself, and they'll be the only actual two hoses that come through the firewall. Undo the clamps. Likeliness is that this has never been done before, so you're going to have to cut the hoses with a razor and unpeel them. Get new heater hose from the autostore and eight clamps. Marvel at the advancement clamp technology has had since the late eighties. Now you're going to pull back on the heater assembly and it's going to come right off, very easily. Take the heater assembly to a clean, flat place where its pieces are not going to get wet or lost. There are a set of metal clip fasteners that go around the housing that hold the two halves together. These things pop off with a flathead. Don't let them go flying off anywhere when they do, either. These two halves come apart, and when they do, the doorflaps that move about to open or close various ducts come loose and will be hard to reallign. You'll see the heater core, since hopefully you already have its replacement and know what it looks like (By the way, in Chicago, $75 is an unheard of, fantasic price for an RX-7 heater core--don't buy them used. You'll wind up having to do this job again if you do.) pull it after disconnecting it's hoses. Since you already bought the heater hose, cut about four inches off to replace the two pieces of hosing with. Pull out the old core and toss it. I suggest that you take this opportunity to clean the heater assembly and core chamber as best you can. Put the new core in, change the valve, and reconnect the piping and the hoses and ditch that stupid two wire clamp that Mazda used and use new clamps instead. That should use up half of your clamps. Now put your heater assembly back together, reverse of how you did it. Make sure the flap doors and everything align correctly and maybe disconnect some actuator arms to see if the doors move all right on their own. Reconnect the arms. Now put the assembly back in your car and hook up the new heater hose to the heater core pipes sticking out of the firewall. Now you can go backwards with these instructions to put everything back. And that's why this project costs a thousand dollars for a shop to do. :P
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10-22-02, 11:30 PM
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Thanks to both Matlock and JumpyRoo for taking the time to track this thread and help me and anybody else doing it for the first time... yeah I wasn't expecting it'd be "fun" in the traditional sense, but seeing as its one more step towards independence from paying out the wazoo, I'm excited. Now if it didn't all have to go on credit cards anyway...
As for where to get it... I don't have either of those stores around but there are a number of Mazda-specific parts stores around that might be able to get me a decent price. I'll be making some phone calls between now and the weekend, and I'll keep regular updates on the progress here... back w/more soon...
A brief O.T. rant: I just found out that whoever did the brakes on this car last totally threw away both the V-clip AND the anti-squeal shims from my rear brakes... GRRR!!!
As for where to get it... I don't have either of those stores around but there are a number of Mazda-specific parts stores around that might be able to get me a decent price. I'll be making some phone calls between now and the weekend, and I'll keep regular updates on the progress here... back w/more soon...
A brief O.T. rant: I just found out that whoever did the brakes on this car last totally threw away both the V-clip AND the anti-squeal shims from my rear brakes... GRRR!!!
10-27-02, 01:51 AM
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NAPA - $140 plus shipping (it was ordered direct from their factory). 2 year warranty.
It was the ONLY place in the entire Atlanta area that carried aftermarket heater cores, and the Mazda dealers wanted $280.00 + for the darn thing. So I did the best I could. AutoZone is said to offer lifetime warranties on their heater cores, but they couldn't order one for an RX7.
Overall, though, I am not TOO pissed... even though the thing looks like a toy and probably only cost $25 to make.
It was the ONLY place in the entire Atlanta area that carried aftermarket heater cores, and the Mazda dealers wanted $280.00 + for the darn thing. So I did the best I could. AutoZone is said to offer lifetime warranties on their heater cores, but they couldn't order one for an RX7.
Overall, though, I am not TOO pissed... even though the thing looks like a toy and probably only cost $25 to make.
10-28-02, 12:24 AM
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FINISHED!! (I hope!!)
Okay, I just finished the install tonight. WOW what a pain. Now that I've done it tho, I know how to do it right next time. It would have been virtually impossible for me to do the "easier" way.. as I was pretty confused in general by the arrangement of the dash, and my 6'3" body doesn't fit so well upside down in the cockpit. So a very good friend and I opted for the long, painful, and tedious method of removing the entire dash, and pulling the heater unit. It went pretty well, except I broke the defogger grilles by accident (they were SUPER brittle), and I ended up needing a few extra screws which weren't there in the first place.
-- sidebar -- somebody else has really done a number on this car.. I find screws missing, shoddy trim repairs, and odd little mistakes all over it - I got pretty ripped off by a "friend" when I bought this car, but I love it so much I don't care. -- end sidebar --
Including the run to Pep Boys for some hose needs which I forgot, and a run to Sears for some tools which broke in the process of getting the dash out, the entire process took just under 12 hours. Having the right tools and knowing what I'm doing now I'm sure it would take a LOT less time. I also spent a little time rewiring my aftermarket stereo system and cleaning the cabin.
So, the end result was that I took it for a 15 minute test drive. I drove it nicely at first, and when it proved no trouble I really beat on it and let it get nice and warm. Throughout it all the heater kept up a nice steady stream of hot air, no apparent leaks anywhere.
As for the valve you mentioned... I looked at it pretty good and it seemed perfectly fine. It looked almost new in fact. So I didn't bother getting a new one.
So, thanks to all of you for your info, ideas, and encouragement, and a special thanks to my good friend Mike for helping me all 11+ hours of the project on a weekend (although he'll probably never read this - he owns an impala and is happy with it). Viva la Rx7club!
-- sidebar -- somebody else has really done a number on this car.. I find screws missing, shoddy trim repairs, and odd little mistakes all over it - I got pretty ripped off by a "friend" when I bought this car, but I love it so much I don't care. -- end sidebar --
Including the run to Pep Boys for some hose needs which I forgot, and a run to Sears for some tools which broke in the process of getting the dash out, the entire process took just under 12 hours. Having the right tools and knowing what I'm doing now I'm sure it would take a LOT less time. I also spent a little time rewiring my aftermarket stereo system and cleaning the cabin.
So, the end result was that I took it for a 15 minute test drive. I drove it nicely at first, and when it proved no trouble I really beat on it and let it get nice and warm. Throughout it all the heater kept up a nice steady stream of hot air, no apparent leaks anywhere.
As for the valve you mentioned... I looked at it pretty good and it seemed perfectly fine. It looked almost new in fact. So I didn't bother getting a new one.
So, thanks to all of you for your info, ideas, and encouragement, and a special thanks to my good friend Mike for helping me all 11+ hours of the project on a weekend (although he'll probably never read this - he owns an impala and is happy with it). Viva la Rx7club!
10-28-02, 04:03 AM
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Yeah, that valve is something I checked out. You can reach that sucker no problem from the pedal area. No need to do that now. Just disconnect the actuator arms infront of the plastic heat shield so that you can move the arms out of the way of the thing when you pull it off, and that will reveal the valve to you. BTW: A complete or itemized new defroster grill set can be found at Mazdatrix.com in any color for a very reasonable price. They're good people and fast shippers. Now's a good time to take an inventory of all the crap that cracked and stuff so you can eliminate those telltale rattlings of a crack snapple and pop worn, plastic dashboard in the future
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