updates: my engine did overheat around mid-July (i pulled over quickly and stopped, hopefully i was quick enough to save the head block and head gasket). The water pump code came on. So if your prius is running like mine, check your water pump and thermostats! they are so cheap around 200$ and stay away from third party ebay water pump, mine failed after 2 years or so. I documented all info in another post [Please help diagnostics coolant issue | PriusChat] The correct temp should be around 186 on flat highway with AC off, 192 with AC on in summers. Mine numbers were around this 4 years ago, over the years it has gone up, after replacing water pump and thermostat, it went back to its numbers 4 years ago.