My Replacement Heater Core Didn't Fit - Why and What To Do

[bill70j]

I recently posted about my heater core failing and dumping coolant into the passenger side footwell. I had to replace the heater core and also rebuilt the heater box while I was at it.

But the replacement heater core wasn't a direct fit so I made some slight modifications which did the trick.

The replacement core seems to be nicely made. The frame mounting holes are in precisely the same location as the failed unit, which is original to the car. And the heater tubes look to be bent properly. But: 1) One side of the frame mounting flange was canted down by about 10 degrees, and 2) The outlet heater tube was misplaced by 1/4 inch, which was the bigger issue.

Here is what I had to do.
1) Put the frame in the vice and bend the one flange side to be in the same plane as the other three
2) Remove (de-solder) the tube mounting bracket
3) Modify the tube mounting bracket so it fits the heater box
4) Dog-leg the outlet heater tube so it lines up with holes in the heater box and firewall
5) Re-secure the tube mounting bracket to the tubes
6) Install the core in the heater box

This wasn't a big deal, and even though you guys warned me that the replacement box probably wouldn't fit, I was a trifle annoyed. But it worked out OK and I would do it over the same way -- though I doubt I'll have another failure in my lifetime. The photos show some more details.


Here's a stock photo of the replacement frame, core, tube mounting bracket, and tubes


Here's a screenshot of the comparative location of the tube holes in the frame (feeding the header box) - the original vs. the replacement



Here's a rendering of the original tube location and orientation as if trying to install in the replacement frame



Here's the change to the tube mounting bracket, which goes along with having to re-orient it on the tubes. I removed the outer portion indicated above the blue line




Here's a dry fit of the unit in the box

 

[Katfish]

Good info

 

[terrywalker]

So, I said I would let people know the heater core I selected for my 71 Challenger convertible as I stated in @bill70j other post on his heater core replacement. In my 72, I ordered from Rockauto a heater core, Four Seasons 91508. It fit with almost no problems into the heater housing for my 72 Challenger. It looks great. I have not installed it yet. For my 71 Challenger, I ordered a Duralast heater core 94508. I pick it up tomorrow. I looked at the heater cores I pulled out of both the 71 and 72 Challengers and I don't believe they are original cores, so I won't send them to Glen-ray. I'll let you know how the Duralast fits when I get it. See link for previous posts.
Removing a non-AC Heater Box
Here's the ones I removed. Heater core comparison in photo.

 

[terrywalker]

Looking at the fin design on the 72 heater core, that one may be an original. The car was off the road since 1984 that I know of.
Terry W.

 

[Katfish]

How did you "desolder" the mounting bracket?