My engine as long as I can remember hearing it has always made what sounds like an upper engine knock between 1500RPM and 1800RPM. Which leads me to think that it is some balance issue since it only occurs at these rpms. I've driven thousands of miles with this noise and it never gets any worse or any better so I think its fine, but any ideas as to what this is and maybe a solution to remedy it. For further info I use 5W30 Full synthetic usally a better brand not a discount deal.

 

Noise - This is a known problem on some engines for whatever reason. I can post the entire TSB if you'd like.

 

Oh thanks, I should have searched knock I expected to get 100s of results. I will look into doing this fix. Ok after doing some searching on this TSB GM says it will not effect durability of the engine and from what I can find its like 250 in parts alone so I think im going to let it knock.