cool. temp. gauge

I have a 2008 Passion with 28k miles. Driving on the highway for 70 miles, the car stalled out with no warning lights whatsoever. Wouldn't re-start. Had it towed and am now being told by the dealer that it overheated to the point that it literally melted the engine. How could this happen...

Thanks, guys: Sometime ago, I posted a msg. asking for help and info on thread size and on where to find a T-fitting for the engine block for two engine coolant/water temp. sending units in order to install an engine water temperature gauge on top of the dash with a pedestal mount. (The dealer...