2012 6.7 diesel, 50 K miles. I was driving down the and got about a mile from my home when I heard a clank from the engine. I turned around and drove back home. I turned it off. Later that day I cranked it to see if it was still there and it still had the noise and approximately a minute later it started revving I would guess 3500-4000 rpm. I immediately turned it off. Again later I tried it again and it did the same thing about a minute into running it would “run away”.

This is a very noticeable sound. I’m thinking of running it yet again but taking a mechanic scope and listening to locate the sound, but does anyone have any idea what this could be? It is such a low mileage truck it’s crazy!

Side note of frustration lol: it sucks paying so much for these diesels, pay so much for the fuel to put in them, so much for maintenance, and then they break.

 

i personally would not run it anymore if there is a possibility of some sort of mechanical failure in progress. Could be the difference between a $5k repair vs a $10K engine replacement. You could have a failed injector that is spewing fuel into the cylinder causing the run away, that eventually would cause a hydrolock. I'm not a mechanic, but if it were mine, I'd probably get it towed to one for diagnosis making it clear to them not run or run very long.

 

money well spent to scan for codes, you don't indicate any but worth a scan.

I too would check all your fluids and see what that presents.

A tow is probably the best idea.