Originally Posted by Piston_slap
I'm surprised no one has asked what brand of oil you're using.
Here's some history...for pretty much up to about 200K, I was actually using Mobil 1, I bought it new. A few times I used the M1 SUV, but generally reg 5W-30....OCI about 4-5K miles.
After 200K I was starting to get a lash adjuster going bad and I tried some shorter OCI's of about 2500-3K miles. I also tried some T6, Some PYB, back to T6, as well as some M1.
Around 240K I tried an oil catch can for the heck of it and it would catch about 2-3 oz per 5K miles. Then the last 10K miles it wasn't catching hardly anything, then the noises were starting.
Turned out there was a small screen in the lid of the catch can I didn't see. This wasn't the part that accumulates the oil residue, just a simple round filter.
So after that, I found out the PCV was clogged, the valvetrain is almost spotless, but after pulling the pan it was darker than I anticipated.
I tried some ATF, 1 qt ATF to 6 qts oil, quieted the lifter a little but then I just ended up replacing all of them.
I also tried some BG EPR after the ATF to get the bottom end cleaned up and that could have knocked something loose.
I also had some light knocks before all that, some ticks, taps...you name it. After the lash adjusters were replaced, the exhaust manifold, both idler pulleys, it was running real smooth.
I honestly don't know when the current knock started...could have been after a cleaning, thought it was some piston slap...still could be.
The knock doesn't start until after a min or 2 then slowly gets louder....which points me to the early stage of a rod bearing going bad. Sure looking that way.