Originally Posted by Gokhan
Originally Posted by wemay
It's in response to Gokhan advising M1EP was probably a better oil. And by the metrics of PAO, he's right...
I don't think I said exactly that. Base-oil quality is only one of the variables in the equation, even though it is a very big variable and the most dollarwise expensive variable.
I think few Euro-OEM 0W-20 oils are fully PAO-based. 50% PAO is still a very good amount.
Euro OEM 0W-20's oils are more keen on reducing wear than their ILSAC counterparts, as they keep the ZDDP level higher. I also typically see less VII content with them, which translates to a thicker base oil, which also reduces wear in theory. This doesn't necessarily mean than a Euro-OEM oil will outperform a given ILSAC oil in protecting against wear in real-life situations or even in actual bench engine tests.
The strength of Mobil 1 Extended Performance 0W-20 is what it is marketed for—longer OCI's. This is because of the higher-quality base oil and higher antioxidant content.
Moreover, it is hard to beat the research and development efforts of companies like ExxonMobil, which use custom additive packages and go through dozens of formulations before they choose the optimal formulation. This is in contrast to a generic Euro-OEM oil blended by using a generic OEM-approved additive package from a major additive supplier.
However, use the OEM-approved oil when you're in doubt, especially when your car is under warranty.
All VW 508.00/509.00 oils must meet max VW OCI in some countries ("old" European Community countries) which is 36,000km. Mobil1 EP longer OCI is advertisement and it clearly states that consumer should fallow OCI recommendations by manufacturer. It does not mean it will perform for 15 or no 20k in all vehicles or any vehicle. When VW approves oil for VW 508.00/509.00 that means that oil meets that OCI requirement.
The strength of VW 508.00/509.00 oils is that there is actual test whether they can do that OCI, unlike Mobil1 EP as EP is one size fits all oil.