We just had a similar problem corrected on our 2000 PT. The radiator turned out to be a steel frame with a copper core. We also had a problem with the radiator support bracket. As it happens there is a threaded rod used to tie in the radiator. Each end of the threaded rod passes through a rubber grommet. In our case, the grommet had disintegrated and was completely gone ob one end. the lack of the rubber shock absorption generated an oblong hole in the brace and eventually caused the leak. Removal and re installation of the radiator required two men, a small boy and a dog (about 4 hours of labor out and in ).We also ended up having to replace one hose on the top of the radiator. In our case I was fortunate enough to find a radiator shop on Merritt Island willing to allow the the coach to sit beside his shop in a secure area, for several days. I originally expected to have to take the coach to a truck repair shop, remove the radiator, transport it to the radiator shop, repair it, return to the truck repair location, re install pressure test, etc.