Originally Posted by PimTac
Originally Posted by y_p_w
Originally Posted by kschachn
Originally Posted by y_p_w
To a point it shouldn't really matter if the manufacturer's specifications are met. But it is possible to exceed such requirements where it might make a difference. It would be for something like Honda's VCM sludge monsters or other cases where there was a design defect and/or under-spec.
How do you determine that a particular oil exceeds a certain requirement and by how much it may do so?
There must be anti-sludge tests out there. However, those engines were notorious for sludging when used with common API SM 5W-20. Pretty much no reports of sludge with Mobil 1 or equivalents.
Are not anti-sludge tests part of the testing regimen to achieve a certification like SN+?
This is what makes these API certifications important. They involve a variety of tests including anti-wear, deposit control, cleaning ability, and many more.
Sure. However, there were plenty of reports of owners following the OLM and getting dealer oil changes using 5W-20 such as PYB, Mobil Super, Castrol GTX, etc and finding that they were sludging up anyways. From what I heard they didn't sludge up if it was changed more frequently (I don't normally advocate for that, but in this case it seemed to help) or if someone used a more sludge-resistant "synthetic oil".