Okay, so I actually tried running a 6.7 Powerstroke on straight 5W-30 synthetic for a 5,000 mile oil change interval. Everyone at the shop said I was nuts and it would shear down to nothing. The UOA came back with better wear metals than the last run with 15W-40. I'm not saying it's a new rule, but it made me question a lot of the 'always use heavy oil' talk. Has anyone else run a modern diesel on a lighter grade and checked the results?

3 comments

3 Comments

Man, that's awesome to hear your test worked out. It's crazy how much old advice sticks around even when the engines change. Getting real data back like that is the only way to know for sure. You're gonna make a lot of guys at the shop scratch their heads with that report.

robin6281mo ago

Right? @anderson.piper gets it, people just hate changing their minds.

robin5911mo agoMost Upvoted

Read an article about how confirmation bias makes people ignore new info. They just dig in deeper on old beliefs even when proven wrong. Getting real data is the only thing that cuts through that.