Apparently I'm a "contrarian" ......I've always beliieved in synthetics and extended drain intervals. My mother's Citation 2.8 was given away at 220,000 miles having no more than annual Mobil 1 oil changes and the normal interval filter changes and top offs.
The only factor that stopped me from an EXTENDED drain interval was convenience. My house has a fleet of operating automobiles. My wife has a 50 mile round trip commute ...I have a 40 mile. We work different shifts and different days (no one seems to figure out why ..after 23 years ..we still seem "in love"
) and the kids hammer the stuff around town. For me it was "take a number for better service" in the vehicle maintenance dept. This could, btw, be the reason for the OCI not being so extended. That is, I don't know of anyone who has too much time on their hands and most things like this need to be "scheduled". That is, "I want to get the Civic squared away for the winter this weekend" ..since vehicle maintenance is not our only task in life ...just a worthwhile distraction that is required to facilitate it. Hence it may be a choice of a 5k interval ...or 10k interval ..throw in some operator specific severe duty ...???????
...but...
Then I did a UOA on a 9-10k OCI in the wife's TJ ahd found, in spite of the 9+ quart capacity, that the TBN was all but shot. This had me re-evaluate my false confidence in XDI. Perhaps I'm being too critical. After all, it was still okay at that mileage ..but I expected better and was dismayed with the performance.
As I said, I'm a contrarian when it comes to some things. I never buy into the standard "old rule" 3k/3m dogma that sooooooooooooooooooo many "convinced" people adhere to. This convention of thought feels more like being led by the nose to the slaughter (as in sheep). I would prefer to build a superior mouse trap and scoff at the sheep and their predictable behaviors.
I too am looking for the "Holy Grail" ..or my staff that I can raise and part the waters (and no excuses)
.