Originally Posted By: Gokhan
Originally Posted By: PimTac
Originally Posted By: Gokhan
Originally Posted By: NH73
Toyota allowed 0w20 on 10,000 mile OCI. Why couldn't they still do that yet? What do you do before 25,000 miles?
Before 25,000 miles, 10,000-mile OCI's are allowed on non-0W-16 but after 25,0000 miles, only 5,000-mile OCI's are allowed on non-0W-16. My guess is that around 25,000 miles, deposits and sludge start to form and they want the highest-quality oil to reduce them.
With every generation, oil quality increases. 0W-16 or more like API SP, which has been delayed, than API SN. TGMO 0W-20 is Group III but TGMO 0W-16 is GTL. M1 0W-16 went even higher in base-oil quality to PAO. On top of that, 0W-16 uses the latest additive technologies not available in many 0W-20's, if in any 0W-20 at all.
If TGMO is made by Mobil, wouldn’t it be using antiwear additive from them as well? Besides, baseoils are usually blends of different groups. The final judgement are the certifications which point to a performance standard.
As long as a oil meets or exceeds the standards it specifies the actual composition of the base doesn’t mean much.
API SN and TGMO 0W-20 SN were introduced in 2010. A lot has changed in the base-oil and additive technology in the last eight years, with the oil and additive companies working hard to transition into ILSAC GF-6.
0W-16 didn't even exist then. It was supposed to be introduced in GF-6B but since that was delayed, they introduced it now. It's similar to the introduction of API SN PLUS, which is due to the delay in API SP.
What people need to understand is that oil certifications aren't born out of thin air. ILSAC and API aren't an independent entities as some imagine them but merely a collaboration of companies like Toyota, GM, Lubrizol, ExxonMobil, etc. Therefore, when Toyota introduces 0W-16, they are doing research and development on it for many years in collaboration with the additive and oil companies. They aren't just going into a store and picking up a brand-new viscosity grade that was never used before. So, yes, the SN rating is not the whole story. That's why Toyota doesn't allow 10,000-mile OCI's on TGMO 0W-20 SN, despite its SN rating. OEM's and oil specs go hand-in-hand. That's why many OEM's simply prefer to have additional OEM specs, something which Toyota hasn't started yet.
It's always safe to follow the owner's manuals and warranty & maintenance guides. If Toyota says that you can only do 10,000-mile OCI's with 0W-16, that's the last word on this matter. There is no point in insisting or consulting to the opinions in the Internet on that only the SN rating matters and the viscosity doesn't matter.
People who are familiar with Toyota's already know the background in this. This is no different than TGMO 5W-20 vs. TGMO 0W-20. The latter is synthetic and the former is conventional. They are both SN but Toyota only allows 10,000-miles OCI's on the 0W-20 because it's synthetic. Yet, "synthetic" is neither an API nor an OEM certification. The story is the same for TGMO 0W-20 vs 0W-16, the latter is a "better synthetic" than the former. Even though "synthetic" or "better synthetic" are not API certifications, Toyota implicitly enforces the requirement of a better synthetic for longer OCI's, just as they enforced the requirement of a synthetic for longer OCI's for 5W-20 vs. 0W-20.
So now, 0w20 is inferior to 0w16, which may be true. But it doesn't answer my question into "Why in my RAV4 says I can go 10,000 miles on 0w20. Did Toyota just realize that 0w20 isn't up to the task on a 10,000 mile OCI? If that the case, they should shorten my OCI.