I've seen worn-out Diesels suck up enough of their own lubricating oil to run on it, with the fuel shut off. That situation usually results in a severe overspeed condition, with parts flying in all directions. Get it rebuild before he hand-grenades the engine!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!