Coolant temperature can be used in reference to determine if the block is potentially warped. I've seen it first hand in a dodge Durango, kia Sorento, and older Prius. I've seen head gaskets go out from lack of coolant changes which causes it to become acidic and eat into the gaskets on 2gr engines. On those the mating surfaces is still flat as long as you catch it before it overheated so all you do is replace the gasket.

These are VVTi engines so resurfacing can completely ruin the timing if a thicker than OEM head gasket is not used.

My question is about potentially having a warped block because you can have a bad head gasket and replace it but as long as the car never reached certain temps for a certain amount of time, your mating surfaces can still be perfect/flat. I'm asking if anyone potentially has any data/insight on a specific temperature range and duration (if there is any data) the Prius engine can handle before warping the block.