by Fish'n Jim on 2022/9/30 12:00:35

I'll bet he was seeking an quick, clear, and easy answer...
Pandora's can-o-worms!
ha, HA, HAAA!
I believe motor oil is one of the most heavily marketed fluids to the macho motorhead. Brand loyalty is a virtue to marketers.
The only bona fide motor oil issue, I can recall, was when the PA source oils which had a high parafin content were in wide use and there was sludge that accumulated on the colder valve covers due to "reflux". They reduced the parafin content by refining more and problem disappeared.
They meet the grade they're made for which ties to an application that was tested. Even within those groupings aren't a lot of differences, mostly newer formulae.
Snake oil has been around since snakes.
I used to have access to SAE, but retired now. But a trove of info there.https://www.sae.org/standards/content/j183_201708[/quote]

I wasn't expecting anything of the sort! Honesty I had no idea of what to expect, but I certainly got some interesting information! I'm now entirely comfortable with sticking 10w-30 in the car. It's nice, it's the same oil as I use in my little dinghy, so I don't have to keep multiple stocks lol. I also figured that a lot of the talk I was seeing on the internet was bogus; snake oil is a real phenomenon!

What that guy said about full flow versus bypass filters is certainly interesting though. I had assumed the automotive industry moved away from them for legitimate engineering reasons, but the more I learn the less this seems to be the case, and the more it seems like modern oil formulations are designed to compensate for the full flow filter's failings.