ky ed
Extreme Adventurer. E27 trailer sailor from Iowa
I would start with pulling heat exchanger and taking to radiator shop or at least making sure its clean and check anode, its something that should be checked annually at least every couple years. Also the cap can be checked. The mating surface on header of tank must be pit and corrosion free. If there is even a tiny leak in any of coolant system your puke tank will not function do to drawing air when cooling off. Remember air can leak and fluid not. Beings your on the hard relax you've got plenty of time to troubleshoot. Check all hoses and replace any suspect hoses and check nipples for pitting. Also because you ran her hot till she steamed and absolutely no water flow. You should also check hoses on exhaust. Hoses have a tendency to have inner liner come loose and partially blocking exhaust. You can always get a loaner radiator tester kit at auto parts store, simple to pressurize system and make sure no leaks