TE,
A very, very large percentage of diesel powered coaches, especially the rear radiator versions like you and we have ('04 Itasca Horizon 36GD with the CAT C-7 330HP), were fitted from the factory with a radiator that are a combination of plastic and aluminum radiators. The tanks are plastic and the core and flanges are aluminum. Typically, when the aluminum sections, ANY section, starts to leak, YOU'RE TOAST! There's very little that can be done. While aluminum CAN be welded (not "brazed"), in these cases, it's just feasible to even attempt it. There's a bunch of logistical reasons why not.
We purchased our coach close to 15 years ago with less than 40K on the clock and shortly after we'd purchased it, it too developed a leak, yep, in the lower left corner. Well, I was new to rear radiator stuff and it took me about 6+ hours to get that beast out of there. When I finally got things cleaned up so I could perform a closeup inspection, I'd found severe corrosion (not rust) at the pinch-flange and the tubes near the bottom left corner. Now, I've been a TIG aluminum welder for years and I could have possibly done this repair.
But, I took it down to a reputable radiator repair shop in the next town over from us near San Diego. And by the way, whoever stated "radiators are cheap" apparently doesn't know a lot about diesel coach radiators. At that time, around 15 years ago, the replacement radiator, plastic and aluminum construction, was right at $1,750 from Freightliner and, it was at least 6 weeks out. When the head tech at this reputable radiator shop looked at mine he stated: "JUNK"!!! I was a bit shaken and said, "junk"? are you kidding, I can weld it but I thought I'd let the "pros" take it on.
He laughed and said: "If you can successfully weld that, you're coming to work for me and pointed to a shelf in his establishment that had at least 100 old ALUMINUM radiators in disarray. Well, that let the air out of my balloon for sure. He said, let's go in and see what we can do for you. He sat down and jumped on his computer. While he was looking, I'd informed him I'd already found out the Freightliner part number, cost and "estimated" delivery date. He said, "you don't want their junk either". Within about 2 minutes on that computer, he'd found an exact replacement for mine.
He said this one is "Copper/brass" and, I asked, OK, how much and what year can I expect it. He stated, $1,200 and I can have it tomorrow morning!!!!! It took me about 5 seconds to say yes.
That copper/brass radiator has been in that coach now for 15 years and right at, 127,000 miles and it cools every bit as good as the aluminum one it replaced.
I tell you all this because, I don't know your travel habits and or distances. But you DON'T WANT TO BE STRANDED because YOU WERE CHEAP! You consistently want to arrive at point B, after you've left point A, EVERY TIME. I have no idea what a replacement radiator for yours and our coaches are today but, back then, while $1,200 even seemed high, it was what it was and we've had many, many trouble free miles from its performance ever since. Good luck.
Scott
