Chevy knock

[FloridaSilverado]

I have an 04 z71 with the 5.3 and 4L60e in it and it just recently started making this noise, anyone have a clue what could be causing it? Rod bearings, main bearings, timing chain?

[diyer2]

With it running start pulling plug wires one a a time, if it changes that cylinder has a problem. Lifter, rod, cam, piston pin? Timing chain is on front of motor.

[rjgti]

could be a hv leak, sounds like it is at 1/2 crank speed...maybe lifter

[FloridaSilverado]

Hvac?

[FloridaSilverado]

Heres a new vid:

Sounds like its coming from above oil pan under the crankshaft pulley. Probably a rod bearing?

[Nanotech Environmental]

Does the frequency match engine speed and get louder as engine speed increases?

[FloridaSilverado]

Not sure. I havent had someone rev it yet but i will check. I pulled the oil pan yesterday and all the rod bearings were good. Oil pump pickup tube oring had a little slit in it. Stil lwaiting for rtv to dry then i will fill it up with oil and see if its still there or not

[FloridaSilverado]

It does change speed when it is revved. Sounds like a hollow tapping kinda

[00Silverado4x4]

Just for the giggles of it all, what is oil level and condition? Maybe just a matter of needing an oil change or it's low? Probably not either of those but cheap check to verify.

[FloridaSilverado]

Changed the oil when i pulled the oil pan to check the rod bearings in it.