AC equipped X1/9 heater core

Dr.Jeff

True Classic
The heater core in the AC equipped X is different from the non-AC core. My AC heater core is now leaking from the core portion so I'm looking for options. New AC style cores do not seem to be available (at least not that I could find). So I'm looking for other possible replacements.

There's a great thread covering the rebuilding of the AC box (https://xwebforums.com/forum/index.php?threads/ac_heater-box-rebuild.20043/#post-161908), but he was able to reuse his old heater core.

And there are threads discussing the use of a 124 Fiat heater core in a non-AC heater box. Unfortunately this won't work in the AC box.

There was a thread asking the same question about a AC core awhile back (https://xwebforums.com/forum/index.php?threads/heater-core-for-86-x1-9-with-a-c.40021/). He had his old one rebuilt by a local shop but apparently it did not turn out so good.

Someone had a supply of 131 Fiat heater cores for sale (https://xwebforums.com/forum/index.php?threads/131-heater-cores-a-bunch-of-them.39292/). The dimensions for them are close to the AC's core size - except for the overall length.

So I'm hoping someone has ideas on what can be used to replace a AC heater core in the X1/9.
Here are it's dimensions:
Overall length at the widest points, not including the hose necks: 280mm.
Overall width at the widest points: 125mm.
Overall thickness: 45mm.

The core itself, without tanks, length: 260mm; width: 120mm; and thickness: 40mm.

The areas for the hose attachments are like those on non-Ac cores, with two "bolt-on" fittings. However the heater valve is not a part of the hose attachments, as it is located separately. Here is a general pic:

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There are more images of the AC core in the first link I provided above, for the AC box rebuild.
Open to ideas or suggestions. Thanks
 

Rodger

True Classic
I had small leak in the one from the AC box that I am rebuilding. I did a pressure test with it in a bucket of water and saw the bubbles escaping from the far end away from the inlets. I took it to a local radiator shop and they were able to solder it and fix it. If they weren’t able to solder it, they said that could take the tanks off mine and get a new core to rebuild it. Not cheap though that way so glad they were able to solder it.
Where is yours leaking?
 

Dr.Jeff

True Classic
The leak on mine is along one of the long sides, about a third down from the end (see pic). It is somewhere under the side frame so I cannot see that actual spot (it's hidden). But that's where the bubbles are coming from (under the frame). For now that is the only leak I know of, however until that one can be eliminated it is difficult to know if there may be more.

008 - Copy.JPG


The seals under the two hose fittings also leak, but I'm not concerned about that.

I'll have to see if any old school radiator repair shops still exist around here. Last I looked for a someone to fix a leak in a rad they all said they use glue these days. Apparently no one knows how to solder anymore. Cost would be another factor. If a new replacement of some sort could be found I'd rather put the money there.
 

Dr.Jeff

True Classic
I did a little more cleaning and inspecting of the box today. I measured what I think might be the largest size of replacement heater core that could be installed without any major modifications. The width and thickness do not have too much room for change, but the length does.

The stock core uses the typical Fiat "bolt-on" hose fittings. They are located inside the box, with the 90* elbow aiming toward the rear. If you used a core that had more typical hose fittings (i.e. soldered on), and stuck them out the side rather than toward the rear, then there is room for a lot more length inside the box. I'll have to take a couple pictures tomorrow to help explain that.

But for now consider the largest heater core to be:
305 mm long x 130 mm wide x 50 mm thick.

So with keeping in mind that the position of the hose fittings (barbs) can be accomodated somewhat, and the overall dimensions are no larger than listed above (it can always be smaller), what might be some cores from other vehicles that could work? This is one item I don't have any good references for, so I'm hoping someone can assist in the search.

Pics and more details to follow.
 

Dr.Jeff

True Classic
Given there are no direct replacement heater cores for the "AC" style box, a retrofit of some sort may be necessary. After searching for options online I realize the "width" of the stock core is by far the biggest issue. The "AC" style core is really narrow compared to pretty much every other one out there. I took pics to illustrate how optional heater cores might be used.

Here's the X core next to a VW Mk1 Golf core. The red lines show what I mean by the "width". Otherwise the length and thickness are almost the same:
001.JPG


Unfortunately the width of a replacement cannot be much greater than the original one. The way it sits in the box there are panels on both sides. Here it is with the upper portion off:
002.JPG


So the bottom side of the core sits directly on the lower portion of the box:
004.JPG

In the above pic you can also see that one end of the core rests against the side wall of the box (red "X"), but there is a little room for a thicker core (yellow line).

And here is where it rides against the upper portion (difficult to tell what's what here). The core rests against a panel at the arrows, so it's overall width is restricted on both sides:
005.JPG


As for the length, we've seen already that one end rests against the box side wall. The other end is where the hose pipes are. There could be some room there (blue line) depending on the style of hose connections [more on hose connections later]. And if you look to the left of the core you can see the extra space for a little thicker core (not marked here):
003.JPG


Therefore when considering other core options as a replacement (e.g. from other vehicles), the size needs to be pretty close to the original. No room for any wider, a little room for thicker, and some room on one end (where the hose connections are) for a bit longer. The largest dimensions without major modifications of the box are:
305mm long X 130mm wide X 52mm thick.

However if some modifications were made to the box, then a wider core could be fitted. The panel that the core rests against at the upper portion of it could be cut out and moved up. Here is the same pic as earlier, showing where I'm referring to:
005.JPG


This is another view of that panel, looking from above. The core (blue arrow) is under it, and the top of the core rests under the area where the red letters are (from the other side). The yellow line shows how much the panel could be moved up, allowing for a wider core:
006.JPG


Same panel from the other side, with the core removed:
007.JPG

008.JPG


This may be critical because as noted earlier the narrow width of the X's core is a major factor in finding a replacement. But moving that panel up is a sizeable modification to the box.

Regarding the hose connections. Here is how they exit the box in stock form (red arrows):
009.JPG

Looking at that last picture, if a replacement core had connections that were on the end of the core - pointing straight up (or down) as many other cores do, then they would exit the box where those blue circles are (either toward the top or the bottom, depending which way the core is installed). The hoses would need to be rerouted, but we're going to have compromises no matter what.

Here is the VW core in place to show what I mean by the hose connections pointing "up" through the box:
011.JPG

This style of core (with pipes like that) seems to be the most common is smaller sizes.

More about core options in the next post. Hopefully these pics give some perspective to how the core is oriented and what the limitations are.
 

Dr.Jeff

True Classic
When I was searching online for suitable replacement heater cores I found one application that is very close to fitting. It isn't really common here, but it is in other parts of the world. It is from several European Fords from the late '80s to the early 2000's.

The dimensions are...

Length: about 302mm including the hose fittings, or about 260mm not including the fittings. This should fit the box without too major of mods. The hose fittings point straight up like the VW one I showed in my last post. So the holes in the box need to be moved, and the hoses rerouted.
Thickness: about 42mm. This will fit easily.
Width (the most critical dimension): about 132-134mm. Just barely too wide, but so close maybe it could be squeezed in with only minor mods. It will really depend on the exact size and shape of it.

Note I said "about" for all of the dimensions above. That's because depending on the manufacturer the size will vary slightly. Also it is difficult to know exactly what the true dimensions are because each brand seems to measure from different points. I even find conflicting dimensions in the same listing at times. So I guess you won't know how close this core will fit until you try.

The unit runs about $25 USD, with shipping from Europe on top of that. So far this is the closest option I've found. But there are countless applications so maybe something even better exists. If anyone has access to heater core dimension charts that would be the best way to search (sadly I don't).
 

kmead

Old enough to know better
When I was searching online for suitable replacement heater cores I found one application that is very close to fitting. It isn't really common here, but it is in other parts of the world. It is from several European Fords from the late '80s to the early 2000's.

The dimensions are...

Length: about 302mm including the hose fittings, or about 260mm not including the fittings. This should fit the box without too major of mods. The hose fittings point straight up like the VW one I showed in my last post. So the holes in the box need to be moved, and the hoses rerouted.
Thickness: about 42mm. This will fit easily.
Width (the most critical dimension): about 132-134mm. Just barely too wide, but so close maybe it could be squeezed in with only minor mods. It will really depend on the exact size and shape of it.

Note I said "about" for all of the dimensions above. That's because depending on the manufacturer the size will vary slightly. Also it is difficult to know exactly what the true dimensions are because each brand seems to measure from different points. I even find conflicting dimensions in the same listing at times. So I guess you won't know how close this core will fit until you try.

The unit runs about $25 USD, with shipping from Europe on top of that. So far this is the closest option I've found. But there are countless applications so maybe something even better exists. If anyone has access to heater core dimension charts that would be the best way to search (sadly I don't).

And the car this alternate fits is???

So much detail but not THE detail? :)
 

Dr.Jeff

True Classic
And the car this alternate fits is???

So much detail but not THE detail? :)
Ha-ha, guess I forgot to include that part...sorry. Or I could be like some members and keep it a big secret, so I can buy them cheap and resell them to other members at a huge markup. :rolleyes:

Actually it fits a rather long list of vehicles, all of which we never got. And there is also a long list of factory part numbers for the same part. But apparently there is no longer a genuine "Ford" part available; the factory part numbers all bring up various aftermarket brands of it. So I think the best way to identify it is by a common makers model number: Nissens # 71755. That should also bring up a list of compatible competitor part numbers.

Like I said before, there is some vagueness about the actual dimensions. Different brands seem to vary in the final size. And some even contradict themselves on the dimensions. For example the Nissens # I just gave...in the Nissens catalog the description states it is 242 x 132 x 33 - same as other brands version - but the illustration in that catalog is this:

30_1024414.jpg


Note the different dimensions. When I did more research I also found other dimensions for the Nissens part that are not the same as either of those, they include the water necks (the overall outside dimension). Judging by that I think what's in the description seems more likely to be correct.

Something interesting about that part. Notice how one end has mounting tabs. You could cut them off if they interfere. Or you could make a hole in the side of the heater box and mount the core from the side - where it can be removed/replaced externally without removing the box from the car.

Here is a photo of it:
384271_1.jpg

EDIT: See this page for additional info on the Nissens part: https://www.eparts.lv/eng/heat-exchanger-interior-heating-nissens-71755. The drop down tabs include a long list of optional part numbers and vehicle applications.
 
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Dr.Jeff

True Classic
Since this thread is about replacing the AC equipped X1/9 heater core, I will cross-post some info I posted elsewhere about removing the AC style heater box from the X. See post # 17, 18, and 19:

 
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kmead

Old enough to know better
Hmm. Yeah the Escort 2 wasn’t available here. I like the idea of being able to haul it out the side without disassembling the entire assembly. One wonders about needing a bleeder to assist with the inevitable air bubble.

Nice find.
 

Dr.Jeff

True Classic
Hmm. Yeah the Escort 2 wasn’t available here. I like the idea of being able to haul it out the side without disassembling the entire assembly. One wonders about needing a bleeder to assist with the inevitable air bubble.

Nice find.
Regarding making the core removable externally. I'm hoping if a new core can be sourced then it will last long enough that there shouldn't be a need to remove it again.

When you mention needing a air bleed, do you think there will be more trapped air due to the changed arrangement of the hoses and nipples? Otherwise this is the same design as the stock core so there shouldn't be any additional trapped air. Or are you just referring to the general nature of trapped air in the X's cooling system, regardless of the heater core design?
 

kmead

Old enough to know better
Regarding making the core removable externally. I'm hoping if a new core can be sourced then it will last long enough that there shouldn't be a need to remove it again.

When you mention needing a air bleed, do you think there will be more trapped air due to the changed arrangement of the hoses and nipples? Otherwise this is the same design as the stock core so there shouldn't be any additional trapped air. Or are you just referring to the general nature of trapped air in the X's cooling system, regardless of the heater core design?
Having both outlets pointing straight up means there is no way to avoid having a loop, the existing arrangement is effectively flat for the AC system (unlike the non AC cars which has a significant upward loop).

I don’t have an issue with air trapped with my cars, the X is much easier to bleed than my 124 or at least is less finicky about it.

Just concerned about making a new problem. I think it can be worked around.

This is a nice find. Thank you.
 

Dr.Jeff

True Classic
Having both outlets pointing straight up
I was considering having the outlets pointing down. Looking at the box it could be done either way.

There is another core (Nissens 71761) that's very similar but a tad smaller overall. However I'm not sure if it will fit the box any better because it is still a fraction too wide. At least on this one the description and illustration both show the same dimensions, so maybe a little more confidence about the size. Look at the info in this listing:

But it appears to be even less available than the first one, which isn't exactly a really common item either. The first one (#71755) is available on eBay:
 

Dr.Jeff

True Classic
By the way, something else I forgot to post earlier....

Back in post #5, when I was describing how the box might be modified to allow wider cores to fit by raising the roof panel above the core (yellow line):
1620176688706.png


The available space above that panel is about 20mm. So this would effectively add 20mm more to the existing maximum width of 130mm, or a total width of 150mm. For comparison, the VW core I pictured in post #5 is 160mm.
 

Dr.Jeff

True Classic
I had a little time to look into the Ford heater core (see post #8) some more today. Based on the best dimensions I can ascertain for it, and a careful re-measurement of the box, I don't think this option will work without doing some mods to the box. The core is just too wide. And if you raise the panel above the core (see posts #5 and #15) to clear it, then you might as well raise it all the way up and open things up to more possibile core options. Also I placed the box back in the car to see how the heater hose routing might work with the Ford core. Previously I had the thought of positioning the hose nipples downward, but there isn't enough room to do that. So they would have to go upward, which is also a bit cramped (this core has really long hose pipes). And as Karl mentioned that may create a air trap.

Therefore finding another core option may be better. I'm sure there is something out there. If anyone has access to a core manufacturer master catalog then you may find a appendix with their part numbers listed by dimensions.

Given the difficulty so far in finding a good optional core, I decided to look closer at the possibility of repairing my old one. As far as I can tell it has one leak. So I gained better access to that spot and I'll attempt a repair like you would on a radiator.

018.JPG


The aggravating part is I can't fully test it until I can replace the seals for the hose connections. They leak so badly it won't hold any pressure in the core itself. I tried using O-rings in place of the factory seals. That actually worked fairly well...maybe better than the real seals? But to better test the core I'll have to order some new seals first.
 

Dr.Jeff

True Classic
I've been doing other tasks on the HVAC box since this discussion, so I'm just now reassembling the box.

I noticed something regarding the possible modification of the box to accept a wider heater core. Earlier I noted the panel over the core has about 20mm of open space above it, so that panel could possibly be cut out and relocated up that distance to allow a larger core to fit under it (see posts #5 and 15). However today I realized that isn't possible. When the box gets fully assembled the AC evaporator core lives in the chamber above this, and comes part way down toward this area. So there is only more like 5mm of free space above the panel. Therefore modifying the box will only yield a small gain, which may not open the list of potential replacement heater cores much. Not good news for alternative cores, although the Euro Ford example discussed seems like it would fit with this ~5mm modification.

I also noticed something else with the stock box design. I'll post it to the thread about adding a filter to the system:
 

Dr.Jeff

True Classic
A little update on finding a replacement heater core to fit the factory AC heater boxes.

At this year's SEMA/AAPEX shows I had a nice conversation with the head of marketing for Nissens. Not Nissan cars, but "Nissens", a Denmark company that specializes in making heater cores among other products:

She was very generous in helping us find a suitable replacement core for the AC equipped X. Apparently they have some products that are not offered in their general catalog listings, plus an extensive cross reference by part numbers. Therefore she asked that I email her all the particulars about this specific application and she will do some searching to see if they can help locate a good replacement. I'll contact her in about a week (after she has had time to recover from the trip) and see what she can find for us. Stay tuned.
 

lookforjoe

True Classic
I may still have an AC- version core - I bought one from MWB, but there was nothing wrong with mine besides the gaskets on the elbows.
 
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