lazydavid wrote: ↑Mon Jan 08, 2018 9:54 am
They can't assume the use of synthetic oil when they don't specify it as a requirement in the manual. If you want to use synthetic AND have an OCI of 6k, that's up to you. But it's unequivocally overkill, just as a 3k interval would be for conventional oil.
They do specify it in the manual, by default: 0W-20 weight automotive engine oil meeting API/SN and ILSAC/GF-5 specification is only available in a syn blend or syn. Also, I don't think that a 6K mile syn/syn blend oil change on a turbo engine is necessarily overkill.
You're preaching to the choir regarding extended OCI's and synthetic engine oils. I've been doing it for years on vehicles outside of warranty. On my turbocharged vehicle I'll be running an oil analysis if go that route. However, if you own a vehicle under warranty, you'd better not be extending the OCI beyond the auto manufacturer's recommendations. Also, the trend in the industry now often requires a specification that, at a minimum, already requires a synthetic or syn blend to meet it. How much of a blend is anyone's guess, and the oil mfrs don't always say. The point being, if the vehicle was already spec'd to use a syn blend, a better synthetic is not going to appreciably extend the OCI--perhaps not even enough to even warrant the expense of an oil analysis--so why try to game it.
I question the replies advising the OP to save money by changing his own oil as that wasn't part of the original question. I seriously doubt if the OP had an inclination to wrench on their own vehicles we'd have to explain how one might save money by doing so. And if one has no inclination to wrench on vehicles, why on earth should they start just to save a few bucks on an oil change? We all pick our DIY projects that we're comfortable with. I'm not sure changing out oil is the right one for someone who has no inclination for it. We're talking maybe saving $30 or so two or three times a year: really not hardly worth the mess, the time, and the effort for proper disposal...unless one is so inclined. I was inclined to do so for 50 years.