The Stovebolt Site Forums The Shop Area Interiors round heater core

20 years ago you couldn't find new round cores and none of the radiator shops here would work on them (not easy to fix). A friend of mine went to the hardware store and bought something like a 20 or 25 foot roll of 1/4 inch soft copper tubing and a handful of reducer fittings. He carefully wrapped the copper tubing into circles spaced about 1/2 inch apart and then made increasingly larger circles above those, staggering the rows until he had used up all the tubing. Then he soldered on the reducer fittings, fit those to the original holes in the mounting bracket (where he could connect the heater hose) and left it at that. It took a bit longer to warm up, but worked as well as the old one ever did. I think it cost him something like $20 for everything to do this. Later a friend who does HVAC work said he could have bought some clamp on fin material and used that plus 1/2 inch copper tubing to replicate the old core using fewer rounds of tubing. Good luck.