Why no CI/CH-4 diesel rating on Mobil 1?

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Aug 12, 2003
Just wondering, if HDEOs & diesel oils are so great, why doesnt Mobil 1 meet those specs too? As a quick guess, they have an outstanding diesel oil Delvac 1 on the market, why canibalize sales with Mobil 1? That is assuming Mobil 1 meets those specs at all. I am guessing *some* grade of M1 does. [I dont know] Do other high-performance SL synthetics meet CI/CH-4 or does it only go the other way? Why and what is the main difference anyway other than apparently the SAE 40 viscosity and "soot" handling? Thanks.
In all likelyhood, the Mobil 1 probably does not pass some of the tests (most likely the abililty to deal with all the soot) that a diesel engine oil must pass. This is likely even more so the case for the new CI ratings to deal with the new EGR valves on diesels. There isn't a need to formulate the M1 to meet that need, since it isn't the target market and there is a Mobil offering to meet that market. On top of that, most car users see things that work in Heavy diesels and shy away...
I use both Mobil One 5w30 and Delvac One 5w40. The Delvac 5w40 is backward compatible with Mobil One 5w30 SL/SJ ratings. From a ratings point of view the reverse is NOT true. So I would have no issues with using the Delvac One to top off the Mobil One if and when needed. Using a CI4 or CF-4 rated oil in the SL/SJ market is done very rarely, although once you have the common need, it does seem like almost a no brainer. [ October 23, 2003, 07:04 PM: Message edited by: ruking77 ]
TSoA, The short answer is that they would have to use a thicker basestock blend, a significantly different detergent/dispersant mix, and an expensive, shear stable VI modifier. In other words, they'd end up with something much like Delvac 1 anyway. They'd also have to charge about $1.00/qt more for it; driving customers to the infamous Castrol Syntec ... [Wink] The Amsoil Series 3000, 5w-30 is SL/CI-4 rated and also meets VW 502/505, MB 229.3, ACEA A3/B3 etc.
Kinda strange now the M1 5w-40 SUV formula is diesel rated. Maybe I am psychic or Mobil really does monitor this board [I dont know] .
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