Some people just want whatever's cheapest that meets the specs for their EcoDiesel motor oil. Personally, I'd rather spend a little more to get superior protection since I can occasionally run up against harsh conditions without any warning and I plan to keep this vehicle as long as economically feasible. Under the previous oil standard, I'd been running Mobil 1 ESP 5W-30 and have been happy with how it sounds. I'm still a month out before I change that at 20K miles (10K mile interval) and get an oil analysis done on that, but others' oil analysis for that oil has been positive.
I've been digging through oil specs and tests for awhile now to get my head around why the spec change and what oil I'm going to choose.
My theory for why the spec changed (gathered from numerous forum discussions, test data, logic, and anecdotal evidence - troll food, I know) is as follows:
- FCA wanted a unified diesel oil spec to reduce inventory costs.
- Dealer techs were routinely putting in the wrong 5W-30 and causing various failures. Change the spec to 5W-40, mark the oil cap, and get less dunce action, reducing warranty claims.
- 5W-40 protects a little better with regards to high pressure and high shear conditions than 5W-30.
I've chosen Mobil Delvac 1 ESP 5W-40
as the oil I'll be running for meeting the new spec. It is CJ-4 / ACEA E9 / Cummins CES 20081 compliant. It doesn't say FCA MS-10902, but Cummins CES 20081 and MS-10902 are interchangeable ( https://bobistheoilguy.com/forums/ub...-1#Post4155373
). The owners manual says you should use an oil that "meets FCA Material Standard MS-10902 and the API CJ-4 or ACEA E9/E7 or ACEA A3/B4". Even though it isn't labeled MS-10902, it does *meet* the standard because of Cummins CES 20081, so there's no chance of FCA wriggling out of a warranty claim on that basis.
Besides it meeting specs, here are the other reasons I've chosen the Mobil Delvac 1 ESP 5W-40 instead of the Shell Rotella T6 that everyone else seems to be so orgasmic over:
- Higher temperature stability.
- Lower pour point.
- Higher viscosity at full operating temperature.
- Initial TBN is slightly lower, but TBN has not been an issue for 10K mile oil change intervals for this engine in anyone's oil analysis.
- Lower metal additive levels (moly in particular) will enhance the longevity of the emissions equipment and minimize the harmful effects of EGR.
- Sulfated ash percentage is equal to the Shell Rotella T6.
A good chart at Rotella: The world's first ever combined hair oil, foot ointment, and salad dressing - Jeep Cherokee Forum
shows these specs in an easy to compare format.
Drawbacks to Mobil Delvac 1 ESP 5W-40? It's harder to find and is about 40% more expensive than the Shell Rotella T6 5W-40. I'll spend $70 on oil each change instead of $50, which is about a $200 difference over the course of 10 years of oil changes. To me, that's negligible, especially given the added peace of mind that I've given it the best protection I can.
Besides lower cost, fanboy glee, and the slightly better initial TBN, is there any other reason to believe that Shell Rotella T6 will protect better than Mobil Delvac 1 ESP?
PS What's with all these ridiculous oil names for quality compression engine oil? Rotella? Delvac? Is there history or is someone on meth?