Ridiculously long internet search shows only cars approved on the 228.31 spec (bevo), vans may use 228.3, 228.5, 228.51 or 229.3, 229.31, 229.5, 229.51, 229.52. So my guess is they don't consider 228.31 a truck oil for whatever reason. That's all that's available in the common parts stores that I've seen.
I hate that you spent a lot of time searching on the Internet.
MB Spec Sheet 223.2 (from the
BeVo site) shows the OM647 engine and the table of MB spec numbers for the oils. It lists the very numbers you have listed above.
The Sprinter T1N engine
requires a MB approved
228.3,
228.5,
229.3,
229.5,oil.
The next level oils of
228.51,
229.31,
229.51 or
229.52 are also
recommended and approved for use in T1N engines.
From Mercedes: "
Mercedes-Benz 228.31 engine oil is excluded for approval and use in the Sprinter OM612 and OM647 Direct Injection diesel engines, as we have research to show that the oil on these sheets can have a detrimental effect on the components of the engine."
What they mean by "detrimental effect on the components of the engine" is, it causes a sludge problem (among other things not immediately observable). However, it's not THAT big a deal in the US and Canada, or anywhere else that ULSD is found, as the sludge and other issues seem to stem from the higher levels of sulfur.
All of MB's 228.xx oils are considered truck engine oils, but the 228.31 was initially formulated for a specific car engine with a DPF. Basically, 228.31 is MB's upgrade of ACEA E9. Which is more or less CJ4. And it's been reformulated a couple of times since it first came out. Shell Rotella T6 is a
228.31 oil. The T6 is good oil, just not necessarily for an OM 647 engine. It meets the following specs: API CJ-4, CI-4 PLUS, CI-4, CH-4, C4, SM, SL, SH; and an ACEA of E9. But it's MB spec 228.31 oil and is not dual rated (for 228.3 and 228.31) the way many of the 228.31 oils are, and is why MB explicitly recommends against using it. Mobil Delvac and Chevron Delo are both dual rated at 228.3 and 228.31, despite not saying that on the bottle. There are a lot of 228.31 oils that are dual rated that don't indicate it on the bottle, and those are probably what you're seeing the most in the stores.
228.31 oils (even the ones that are dual rated) are not properly read by the ASSYST computer, though. (the ASSYST computer was actually designed and tested using 229.5 Mobile 1 0W-40 oil, BTW). You can certainly get away using 228.31 oil in an OM 647 engine, as long as you don't idle much and you don't rely on the ASSYST for oil change intervals.. You'd just want to change the oil earlier, like every 8,000 to 10,000 miles (if you don't have a used oil analysis done regularly) instead of extending it to 15,000 to 20,000.
My recommendation is to stick to the required or recommended oils listed above (same ones you have found). As long as it's on the list the brand doesn't really matter. I'd try and find out what kind of oil the previous owner used, and if it's on the list I'd stick to that, probably. It's better to stick to one brand and viscosity, all things being equal, than it is to change them frequently, as whenever a new brand or viscosity is used the engine wears juuuuust a tad differently. But that's certainly not a major consideration. Approved oils and regular changes are the primary considerations. But just look at the list of brands and viscosities on the MB spec sheets, and pick the brands you can find locally.
