If you have a copper/brass radiator and you have a torch, a back woods soldering iron (ours is an old one from Radio Shack that runs on butane intended for a refillable cigarette lighter), an old school soldering iron (that you can heat in the fire), a wire brush or sandpaper, flux, and solder, you may be able to solder any pinholes in the tubes or cracks in the tank. Use the brush or sandpaper to clean up the area to be soldered. We found that the thin metal of the tubes with pinholes were easier to repair using the soldering iron. The MAP gas torch got the thin metal hot so quickly that the solder would not stick. Holes in the tank (where the metal is thicker) are easier to fix with the torch.