Originally Posted By: dnewton3
That makes much more sense.
Lesson #1 - UOAs are more accurate than service advisors
Lesson #2 - thinner oils do just fine; the wear rates will likely not be affected to a tangible degree had it actually been 5w-30 instead of a 20 grade.
Lesson #3 - your OCI plan is uber conservative
Lesson #4 - you still have no idea who makes that lube, but does it really matter? To you? Maybe. To the engine? Not one bit.
Perhaps I can take OCI closer to 10k mi. Only way to know would be another analysis around 8k I guess. You're right, I don't know who makes the oil (I can assume Exxon Mobil since they have been in bed with GM for a long time) BUT, I could give a rat's you know what as long as it is protecting my engine sufficiently.