 Restore and protect. Do you have any thoughts on that? I already know the answer to this. You've done all your regular maintenance, oil changes, and everything up to this point, correct? Absolutely. I wouldn't change what you're doing. If I was going to use a high-mile oil, it would be on really a high-mile engine. Not that yours isn't, but it isn't. Really, 90K in a 6-liter is not a ton of miles. That engine will run 300K no problem.