They got it hot somehow (broken belt, coolant leak, who knows) and kept refilling it and running it until all four combustion chambers split. The fire ring blew on cylinder #4 from coolant explosions and continued operation etched a groove across the deck to one of the steam holes in the head, at which point they couldn't keep coolant in the system anymore. It probably has a bent rod or crankshaft, too, but I didn't check. A couple years ago the great People's State of Kalifornia had deemed the emissions from all mobile refrigeration units using this same engine to be a hazard to life, posterity, and the polar ice caps and to be taken out of service immediately, so they were available here in the US for a song with low hours. I didn't buy one because I couldn't confirm the crankshafts were the same, but even having to change the crank would be cheaper than a reman with no core. Used engines of unknown or undisclosed history are still pretty widely available. At some point I'll have to fix this one because the main pump unit is going out in my old one and when it quits completely it will total the machine. The pump on the other one is totally different, of course, and the engine in the one I'm using now isn't in great shape either.