Advice on when to sell (turned into oil deep dive)

[me51]

When I used regular Mobil 1 5W30 in my LS engines, the motors would rattle on start up for a few seconds.

I can confirm that:

Mobil 1 5W30 makes the engine run noticeably noisier overall (incl. about 1sec. cold start chatter) compared to a different brand 5W30. What works well for me is using the ACDelco PF48E filter and any full synthetic 5W30 with dexos1 or dexos2 specification.

I've been running Shell Helix Ultra 5W30 ECT C3 for a while and it seems to work well, but it's probably sold under a different name in the US.