alljeep wrote:
Too bad Jeep may have missed the boad on the correct oil spec. The Mobil 1 0W-40 Synthetic from the factory that came in my 2005 CRD does not meet the CI-4 or CI-4 Plus spec that is necessary to adequately carry the soot in the oil.
This weekend at around 1800 miles I'm switching over to Shell Rotella T 5W-40 Synthetic which does meet all the necessary specifications for closed system diesel engines. Then I'll follow the routine oil change schedule.
The Mobil 1 Truck & SUV oil (which is same oil as Delvac 1) 5w-40 has a better Novac and soot carrying rating then the Rotell T 5w-40 if I remember correctly, but not enough to make any real difference to our Jeeps on these short oil changes of 12k miles. I've looked at the spec's for both Mobil 1 0w-40 & the DELVAC 1 and the soot carring capabilities are not that far apart, the main difference was the 0w-40 had a greater high temp shear strength then the Delvac 1.
Myself I been thinking about using the Mobil 1 5w-40 in the CRD instead of the 0w-40 basically for the same reason of having greater soot carrying ability and it easier to find. One other reason for the 0w-40 was economy and easier starting in winter. Our Jeep is kept in a insulated and heated garaged and when started later in theday for the return home it is much warmer, we don't have many afternoons here that it's below freezing.
Sometimes I just want to scream "Motor oil is motor oil".
Forgot to mention that the Shell Rotella T is a class III oil (which is what any good minerial based oil is) and not a true synthetic as the Mobil 1 and Amsoil oils are.