I've been using Rotella T6 5W40 oil for years in my '02 Dodge Ram with no problems. As I'm approaching 200K miles on the rig I recently switched over to Delo 400 XLE 15W-40 thinking the heavier oil would do a better job on an older engine. The Delo seems to be doing fine, is way cheaper and I have no gripes with it.
Foolishly I started looking over the specs (you can't stop once you start down that rabbit hole) of these newer CK-4 oils and was a little shocked to see the Zinc/Phosphorus levels down under 700 to 800ppm. Seems like the older CH4 and CI4 oils had way more ZDDP than this new stuff...like double. Those AW additives were considered good for a flat tappet engine. Just wondering if I should look for another oil, stick with the Delo, do more frequent oil changes or just stop looking at the specs?
Foolishly I started looking over the specs (you can't stop once you start down that rabbit hole) of these newer CK-4 oils and was a little shocked to see the Zinc/Phosphorus levels down under 700 to 800ppm. Seems like the older CH4 and CI4 oils had way more ZDDP than this new stuff...like double. Those AW additives were considered good for a flat tappet engine. Just wondering if I should look for another oil, stick with the Delo, do more frequent oil changes or just stop looking at the specs?