
Motor Oils - Fuel Economy vs. Wear
Conventional wisdom states that engine oils that increase fuel economy allow less friction and prolong engine life. The purpose of this article is to challenge conventional wisdom, particula…

Good article that makes one possibly rethink their decision to use 20 wt. oils. The punch lines come at the end of the article.
I don't keep my cars long enough to worry about it except my '18 Forester XT. Will go the distance. 30 wt is recommended. I use Euro 0W-40