This sounds like a BS fix. First off they would have to tear the lower side of the engine completely down in order to inspect it. Then dumping heavy oil in it to temporarily hide any damage is a real hoot. That sham started with used car salesman.
If Gm would stop replacing their old proven engines with new junk designs then they would not be in this boat.
Agreed. Heavy oil is something you do as triage when on the road and just trying to get home before it let’s go.