wow. that is just a lot of driving around. any issues with it? what about your own personal comfort? can you show pics of cars interior? are you going to get another prius?
Based on what you described, the engine has a bad head gasket / warped cylinder head, maybe even cracked cylinder head, because you have been driving it overheated for too long. There is nothing that can fix this cheaply, you'll likely need to spend about $2k to rebuild the engine or find a junkyard prius that has the same engine and swap it in, likely about the same cost. Keep driving that car with this engine and you will find yourself stalled on the side of the road. The reason you don't find any more heat is because your engine is no longer running correctly, and heat comes from coolant heat that comes from your engine. I don't know what else the engine coolant circuit is passing through, but if it pass through anything else you can potentially cause damage to those component too if you keep driving like that. I'd find a new junkyard engine or bring it in for a rebuild as soon as possible. There should be enough crashed Prius that has working engine you can pull from all over the nation by now, and any mechanic should be able to swap engine. Those mechanic in a can sealer are only good for external leak (those that don't leak into cylinder), like those Saturn engine with cast porosity. It is not for head gasket.
It's been a while since I checked in - how y'all doing? (practicing my southern accent) Hmmmm, I wonder if his motor came from my car? Unlikely, but funny if it did! Totaled at under 25k miles, but entire front end was good including ICE and CVT.
Have a problem developing. Car appears to be misfiring while driving ease off a little car begins to shudder or shake. Also on occasion when I'm at a stop the engine will turn on on but not register with light showing just as if i pressed the gas while in park. Very strange happened about 5 times. i replaced all spark plugs still has problem. Did not mess with coils. engine will run for about 5 sec an shut off.
At toyota tech is claiming inverter disc dampening is bad which is causing the vibration or stutter. He says he has to remove trans cost of 12 hours would be 2700.00, he is also claiming that any misfire would throw a code. Which my car is not giving a code.