My car is in the shop for valve train noise issues on passenger side - not extreme, but not normal either, does not go away after start up (this is a LS3 engine).
Dealer initially said he would look into oil pressure-blockage issues on that side.
1st report back from dealer yesterday, was they have determined problem is with components associated with cylinder #6 - ruled out accessible top side components, leaving problem to be either a bad lifter or bad cam.
Report today is that the lifter roller pin broke; dealer claims GM is saying only way this could happen is over rev of engine.
I have never hit red line yet (still breaking in <1,200 miles), and only came close to red line a couple times under light acceleration - besides I thought we have a rev limiter.
Anyway if anyone knows of other instances of a lifter roller pin breaking, please let me know. I may have a fight with GM on this. :(