Join Date: Apr 2006
Thanked 170 Times in 167 Posts
Rep Power: 12
Fire the mechanic and, as Cam suggests, make sure an actual tachometer is used. Diesel engines can run away if they suck in too much fuel oil past bad rings and other problems, somehow either a governor is out of whack, or there is too much fuel and air getting into the engine.
A mechanic shouldn't be baffled by that. the guy pretending to be a mechanic, owes you a refund and a beer.