2016 G23 H6DI 450HP Oil Specification???

[thejean]

Rotella T6 5W-40. The end.

I do think that would be a good option as well but my dealer told me I shouldn’t go any lighter than a 15W40, even though in the heat of summer the 15W figure doesn’t mean that much. Given they will be justifying my warranty claims should I have any, I’m reluctant to stray from their advice. Had the T6 been available in a 15W40, I would have likely gone that way and never thought anymore about it.

[RDT-G23]

It isn't lighter; it is full synthetic, and has a lower pour point. Ford calls for 15W-40 on my Powerstroke as well, but you can use 5W-40 full syn. I've plowed this ground with PCM. I'm about to change to T6 5W-40 at 50 hours. It is certainly overkill, since these engines run at 165 degrees, thus the reason PCM sees no need. That said, it certainly won't hurt. Like I said, it is overkill, but I like killing insects with sledgehammers...

[H2O]

PCM engines run at 160*. Automobile engines run at 210*. 15W-40 oil indicates it is 40wt at 210* and it will have less viscosity at 160*. PCM wants their engine oil viscosity somewhere between 15wt and 40wt at 160*. Does it ultimately matter? PCM seems to think so.

[RDT-G23]

PCM engines run at 160*. Automobile engines run at 210*. 15W-40 oil indicates it is 40wt at 210* and it will have less viscosity at 160*. PCM wants their engine oil viscosity somewhere between 15wt and 40wt at 160*. Does it ultimately matter? PCM seems to think so.

Likewise, 5W-40 happens to be ~40wt @ 210* as well, and likewise is somewhere between 15wt and 40wt at 165* (where my boat runs). Synthetics simply have a larger range than Dino oils, but certainly, either will work fantastically in these engines. Synthetics are clearly overkill, as I mention above.

[thejean]

I agree RDT. And I would have gone with a 10W40 syn marine oil but my dealer has advised against it unfortunately so I’ll stick with 15W40 until I’m out of warranty.