This motor as 199K miles and has been trouble free for the most part. I am getting a knocking sound at the cam speed but I don't think it's a rod knock..just a hunch.
What I have done is pull each coil lead and no change in noise. Changed oil and ran some Rotella T6 and 1.5 qts of ATF for about 150 miles, drained and refilled with Castrol Edge.
Did a water injection through vac line and also GM upper engine cleaner in hopes it was a carbon fouled chamber....also running BG44K.
Engine runs smoother but noise is still there. Noise is not audible on a cold start, takes 3 min to start making noise, get loud at roughly 5-8 minutes then gets quieter from there on out..about 60-70% quieter than at the loudest 5-8 min mark.
Did oil pressure test and pressure was very good, 25-30 PSI at idle but this was a sandwich adapter so I wasn't able to measure the pressure post-filtration.
I have had an occasional cold start tick for sometime and the oil change/cleaning has helped. The noise sounds like it comes where the head meets the block, I hear it more on top then under the vehicle but mostly from the drivers door...standing behind the LF fender but my attention is directed to the upper portion of the block.
Could this be a lash adjuster that is bad and ticks when cold? Could it produce a noise that's deeper than a tick but lighter than a knock?
I have nothing in the last two oil filters I cut open.
My harmonic balancer has the slightest wobble...barely visibly but I can see a very small deflection and I would guess .020-.030"
I have a thread going on this but was questioning a clogged filter screen, but I think dedicating it to a knocking noise may yield more results. http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3341529/Re:_Can_I_backflush_an_oil_pic#Post3341529
Also, when I plug the large vac port on top the valve cover, after 30 sec the knock goes away.....very odd.
Also the noise seems to go away above 2-2500 and is most audible from the 600 RPM idle to about 1500 RPM
What I have done is pull each coil lead and no change in noise. Changed oil and ran some Rotella T6 and 1.5 qts of ATF for about 150 miles, drained and refilled with Castrol Edge.
Did a water injection through vac line and also GM upper engine cleaner in hopes it was a carbon fouled chamber....also running BG44K.
Engine runs smoother but noise is still there. Noise is not audible on a cold start, takes 3 min to start making noise, get loud at roughly 5-8 minutes then gets quieter from there on out..about 60-70% quieter than at the loudest 5-8 min mark.
Did oil pressure test and pressure was very good, 25-30 PSI at idle but this was a sandwich adapter so I wasn't able to measure the pressure post-filtration.
I have had an occasional cold start tick for sometime and the oil change/cleaning has helped. The noise sounds like it comes where the head meets the block, I hear it more on top then under the vehicle but mostly from the drivers door...standing behind the LF fender but my attention is directed to the upper portion of the block.
Could this be a lash adjuster that is bad and ticks when cold? Could it produce a noise that's deeper than a tick but lighter than a knock?
I have nothing in the last two oil filters I cut open.
My harmonic balancer has the slightest wobble...barely visibly but I can see a very small deflection and I would guess .020-.030"
I have a thread going on this but was questioning a clogged filter screen, but I think dedicating it to a knocking noise may yield more results. http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3341529/Re:_Can_I_backflush_an_oil_pic#Post3341529
Also, when I plug the large vac port on top the valve cover, after 30 sec the knock goes away.....very odd.
Also the noise seems to go away above 2-2500 and is most audible from the 600 RPM idle to about 1500 RPM
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