Originally Posted by rolandcavanagh
My experience is that the hoses for the auxiliary devices (heater, hot water
heater) come off below (before) the thermostat, and return to a lower pressure point on the block. I'd be looking for a plug
in the original hot water
heater, or a bad coolant pump, but as I once discovered on my GB, a badly installed hose (one with a plastic cap still on the fitting, one with the hose crushed into the fitting) is a possibility. I'd disconnect the hose starting at the pressure (top) fitting and start the engine briefly with my thumb over it and assess the pressure and flow, then work my way through the system.
That's what I did last night. I had another project
I was working on (lavac installation), and decided to start the engine and see what I could see.
Both auxiliary hoses coming off the engine (you were right about the arrangement) got at first warm, and then hot. No heat in the hoses at the appliance end though. I then shut off the engine.
After thinking about it, I removed first one, and then the other auxiliary hose at the fan heater. I got nothing from the first one, but lo and behold, when I removed the second one I got a flow of hot water from the hose.....yay!
It was late, I was tired, and I called it quits for the night. After more reflection I believe you are correct. I think the water heater has blockage in it, do they fail like that often? I looked, but can't find any evidence of that yet.
I need to go back and reroute those aux hoses several different ways to confirm what's happening, but I believe now I can find the problem.
Thanks everyone for the help, I'll post an outcome as well.