Originally Posted By: badnews
I ain't buying an oil that costs three to four times what Rotella T6 will do
If you don't want to give them a reason to deny warranty claims, you'd better stick to an oil that meets their spec.
M1 ESP 5w-40 (Meets MB 229.51 spec) is available at PepBoys for $7/quart if I'm not mistaken. Rotella T6 comes out to about $4.90/qt, so the difference isn't that much, especially if you only change your oil once a year.
Technically, Rotella T6 isn't a long OCI oil, but it's a good oil nonetheless and I'd be surprised if it caused much harm.