That's a beautiful looking car Robert. I'd hope that will never see an salted roads. With that said I see you mentioned "dependable" in the original post. My suggestion would just block off coolant flow to the rear system.
I had a New Yorker with rear heat and ac. They both leaked on me too.
Sorry if I had you worried there because I want the rear heat working. No, this is not to see winter use. But I do drive it up until the first salting and I do like having everything work as it should.... And reliably at that. I know it will get there. Just a bit of time and parts... For the moment, I do have it blocked off.
