The absolute is that using an oil that causes damage will invalidate the warranty. That’s what they publish.
I disagree; the absolute is using the manufacturer's recommended/required oil (my VWs don't give a choice unless it's just top-up oil so this varies w/r to the language used which has been dulled over a bazillion times in various posts here on this topic). My comment is always that if you want as smooth as possible warranty experience with a major engine failure which is incredibly unlikely anyway, this is the way to go. If you use any oil that you want where you delve into details of approvals/specs/etc., sure, you may be just fine but the burden of proof will still fall on you right/wrong IF they got frisky about it....my way works to eliminate that 100%....note that it doesn't eliminate warranty hassles in general. Likelihood of any drama is always low but isn't zero and folks here like to give advice that may be way out of an indvidual's comfort zone w/r to financial risk. Personally? I don't worry about this stuff but that's me. I can't imainge a time where a dealer would balk at a pile of receipts/records for maintenance and go with "but this oil you used isn't XYZ approved" but it could happen so why take the risk is many folks' response. Going through an arduous warranty arbirtation is a possibliity to "prove" the oil you used that went against the manufacturer's requirements/recomendation...you are 100% paying that lawyer to help you, not the other way around. I bet there are so few cases where this was an issue you can count them on a few hands!
