The Stovebolt Site Forums The Parking Lot Big Bolts Heater Core

I'm helping a friend build a car hauler using a 51 COE cab and a Class A motor home frame. I'd like to retain the original heater. Since we'll be using a 12 volt electrical system I'll have to replace the blower motor, which is easy. However, I've learned the original heater cores can't handle more than 4 PSI, so I'll need to replace the core with a modern core. Has anyone out there done this before? I realize an exact fit replacement likely does not exist but I'm hoping someone has done this conversion and tell me what heater core they used. I realize there may be some modification necessary to the heater. I really like the old retro look of the original heater. Thanks in advance for any help.

RebelJD in KC

Hy RebelJD, unfortunately there were different heaters in those days, depending on how much money you wanted to spend and what features you wanted and if you purchased it through the dealer or another source. A picture of the heater in question would help us make suggestions if we have any. As to the pressure the core can handle, yes the radiator cap pressure was 4 p.s.i. maximum, but the core may be able to handle more. Age of core and its life up to this point will dictate what pressure it can handle. I have a catalog of cores with dimensions, maybe such a thing exists on the confusilator somewhere?

For 1951 there were two accessory heaters, they are as shown, reproduction cores are now available for both types. There were numerous other types available on the aftermarket. Arvin, B.F. Goodrich, Montgomery-Ward, Atlas, Firestone and others, cores for those will be less common.
https://www.flickr.com/photos/advance-design_parts_co/8129448404/in/album-72157631868452754/

Thanks 3B, I'll take some pictures and post them.

Sorry, didn't see the reply from the Shop Shark. Thanks for posting the pictures Bob. I have the airflow heater. The name plate says its a Harrison H-02-47. I've disassembled the unit and tested the core by submerging it in water and pressurizing it with a tire pump. It has two leaks from what I can tell. One is on the out edge and would be easy to fix, but the other leak is coming from deep down in the core, not sure how to fix that. I really don't want to have issues with this down the road, which is why I'm looking to replace the core. The one new core I did find says it is not intended for pressure greater than 4 PSI, which is my concern.

If your leak is inside the core, why not try to find a similar size core from a later model vehicle? A good radiator shop should have a heater core manual that gives dimensions. You an always solder your original inlet/outlet necks on the later core if they are unique. That way you will have a core rated for higher pressure. That may be cheaper than getting your original core repaired. Good luck!