New to the forum and this is my first post. I have an 01 1500HD. 6.0 with 220k miles on it. Just recently it has started knocking a little bit. Its tough to tell exactly where it is coming from and sounds like its in a different place depending on where you are listening from, but it does sound more like its in the bottom end. I am by no means a mechanic, but from what little I do know it sounds like a spun bearing, but it doesn't really act like its a bearing. No oil pressure problems, no metal in the oil, no overheating, knocking goes away with increased RPMs, still runs and pulls ok, though it does seem like I have lost some HP and gas mileage. The only other thing I have noticed is that sometimes start up is a little rough. Like I said, the knock is at its loudest at idle, and it basically disappears at around 1500RPMs. It gets little louder once the motor warms up, but not much. Its been doing it for about 3000 miles and I it really hasn't gotten any worse, but its annoying. I have tried different oils and engine cleaners/additives, but nothing has helped or even changed the sound. Does anybody have any other suggestions that could clear this up or is it actually a bearing? Thanks in advance for all your advice.
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unfortunitly it is a problem with the 6.0's i know i have one also 2001 2500hd you are in the same boat as a lot of other gm owner's it has alot to due with the piston design and the clearance's they have to run the new engine's at .you get piston slap .mine is not as bad as your's yet i only have about 45 thousand on it.i think a new design engine is the only thing that could cure it .
it wont happen