I’m more concerned with the expansion rate of the aluminum head vs the expansion rate of the iron block.
Aluminum expands a lot more per degree of C/F than iron.
And the head absorbs a lot more of the combustion heat than the block.

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U.S. Army Retired

Another consideration are all the electronics and plastics etc in the engine compartment As I mentioned aircraft air cooled engines can run 450 F temps but those also use old school technology and essentially no modern electronics just a few sensors and wires even manual fuel mixture screws, chokes etc. They usually also have aluminum blocks though with cylinder sleeves etc.

Point is even if engine can operate with waterless coolant at a significantly higher temp I suspect there would be a lot of electronic failures .

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