Hello, With a 1959 GMC 100 and the heater fan and core assembly were not installed when I bought it. I've taken the heater core to a local shop and they are fixing the leak. They called and asked about some kind of additional valve that I should bring in and they'd weld on as part of the rebuild. The core seems to just fit into the sheetmetal box it's held in so I wonder what it could be. This heater seems super simple. One single control knob on the dash. The heater core has two copper tubes stubs coming out of it that look they'll run nicely through the 2 hole up under the dash on the passenger side where the unit hangs. I have the repair manual and it seems to have no reference to any heaters. Anybody no where I might find a diagram of the 1959 GMC heaters?
