05 Envoy lifter issues

[leegreen]

I'm not an expert on DOD, but I did read up on how to delete it in consideration for using a DOD era engine in a swap. I suggest reading up on what that device does with regards to the lifter oil management solenoid and the PWM torque converter before running it long term or you could be looking at other problems down the road.

Since your noise is intermittent, can probably rule out rockers and wiped out lifter/cam lobe. Those should also show up inside your oil filter, did you cut one open?

What does your oil pressure do when the clacking is heard?
If it drops there may be pressure regulator issue, if pressure is constant there might be air in oil via failing pickup tube o ring which may only show up when oil is hot. Overfilling with oil to the point that o-ring is submerged is a test, but you don't want to drive it that way, so if your noise is intermittent that is not much help

Do you know the history of oil changes?
Gunky engines more prone to AFM lifter failure. At 145k miles your engine should be at midlife unless it has been abused.

Heads need to come off to do lifters, if you are doing lifters you might as well do DOD delete, but you need to do cam as well. Doing cam with radiator and in may or may not be possible, depends how hard on things you are willing to be. Once the timing cover is off the oil pump is right there, but the bolt for pickup tube is hard to get to and you don't want to drop it in the pan. By this point you are looking at a short block in a stripped engine bay and pulling the engine is not that much work.