Bought 2004 CTD motor knocks in the lower rear half of motor. 70,000 miles doesn't look abused. Is there anything else it could be?

 

Sounds like it might be a warrantee item to me.

 

On a common rail injection system if an injector leaks into the cylinder it will cause a knock.

In a gas engine, when an injector continues spraying when it shouldn't, it will make the mixture go rich, may foul out the spark plug, and may wash lubercant off the cylinder, and dilute the oil in the crank case.

In a diesel when that happens, mixture isn't an issue so the fuel will burn, but the added fuel will increase the temp of that cylinder, maybe enough to toast the piston.

At least that's my understanding. I would guess a good mechanic could tell the difference by listening.

I think I've only heard of one spun rod bearing on a later Cummins, so I think bad injector would be more likely.

If it's under warranty, I'd let a good dealer mess with it.

 

Thanks for the help and advice. I hope it is an injector and not a rod. No warranty salvage title vehicle.

 

I just pulled a 2004 apart and fould a dropped valve in number 6. The noise it made wasn't very loud though. It was more like a tapping than a knock.
The best thing this could be, if it is an auto tranny, is loose TC bolts. I bought a truck once, dirt cheap because it had a "rod knock", and when I got it home I found the TC bolts loose. Tightened them and had a great truck, with no knocking.

Chris