66 Ply. vip heater leaking at the bottom of the heater box

rsh1966vip

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Walked into the shop and found a puddle under the 66. Long story short, I found a leak coming from the bottom of the heater box. It is a good thing that I have all the carpet already stripped out. So, I have a couple of questions:
1. How do I bypass the heater by re-routing the heater hoses? This would be a short term fix.
2. Second question....is there a video showing how to remove the heater box? The last time I removed a heater was on a 66 Ford F100 and it was simple, but this Plymouth heater looks way more complex. Where do I start? Maybe someone has a schematic that shows what to unscrew/unbolt first?
Your comments will be appreciated. I will post a pic of the leak and also general pics of the heater.
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Thanks, rsh1966vip





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My $.02, I'd take both incoming and return hoses off at the firewall/cowl and plug. also at the water pump for a clean look, then you can remove the box at your convivence.
 
1. How do I bypass the heater by re-routing the heater hoses? This would be a short term fix.
Easiest way to do this is take one hose off completely. Doesn't matter which one. Disconnect the other hose at the firewall and loop it to the outlet on the water pump.

2. Second question....is there a video showing how to remove the heater box? The last time I removed a heater was on a 66 Ford F100 and it was simple, but this Plymouth heater looks way more complex. Where do I start? Maybe someone has a schematic that shows what to unscrew/unbolt first?

I've never looked for a video. Best bet might be to download a Factory Service Manual from this site if you don't have one. Service Manuals – MyMopar

I'll give you a tip for not making as much mess inside the car... Take a wet/dry vacuum cleaner and put it on the firewall heater hose connection and use it to pull any coolant left in the heater core
 
You got the AC version, I've seen a 1965/66 (no AC) heater box on CL for sale quite awhile and it looks just like my 1968 Fury's so I'll bet they were the same through those years (Chrysler did things like that)
But looking at your limited pictures of your AC box it looks just like my 1968 Fury III wAC. I lucked out on my leaky heater core in that car as it's a 2 part core with hoses that connect the 2 cores in the box and it was just the interconnecting hose rot causing the leak.
Pretty much you have to drop the steering column, undo the 2 L & R lower dash bolts by the kick panels to pull the dash out quite a bit to make working and access easier, just be careful to not pull wires & hoses to far to dislodge and if you have a column shift undo the pointer linkage to not **** up your indicator. Then it's just un-attach everything to remove the box and dissemble on your work bench.

(edit) some say you don't need to pull the dash or drop the column (been through this before) but I found it way easier to get at everything that way YMMV.

(edit #2) Oh and BTW wash & clean the whole box out because if you leave a residual anti-freeze in the box you will continually smell that afterwards. And if you have a working AC you will need to purge & recharge. (not like a GM where you can swing the core out of the way).

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Last edited:
Thanks for the comments. I did the by pass as recommended. I will need to think more about pulling the box out.

rsh
 
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