Originally Posted by LarryBible

Independent testing says that Delo is a better oil, I don't know about being MUCH better though. Rotella has a higher parafin content and Delo multigrade has shown to maintain it's viscosity index improver effectiveness over a longer period of time and heat cycle conditions.

As far as popularity, Delo is used by the truckers every bit as much if not more so than Rotella. In fact I expect that with the truckers Delvac is probably used more than Rotella.

All that said, it is splitting hairs. All of them are excellent oils for a diesel engine. I wouldn't hesitate to run Rotella if that was all I could get.

Have a great day,