Water boils at 212. Under pressure of say a 15lb radiator cap and assuming some
antifreeze (which raises boiling point) it would have to get well North of 250 or so before it would blow out the overflow. 18lb cap would be even higher temp, 20 lb cap, etc.
Again, assuming good hoses, tight connections, they should be able to handle the temp and the pressure.
Worse case scenario? Like HLC said, blowing a hose. If that didn't happen, no big deal. A well built engine should be able to take those temps in stride.
Seems to me I've heard engine
oil temps in excess of 300 or so is not good, damages the
oil in some way.