As long as you understand that the above is really a PR answer (from Mobil) ....
Well, yes and no. Mobil is not my sole source of information. There's a company called ANA Laboratories who has oil analysis labs in several cities, including a research and teaching lab at Murray State.
The problem, many people will change oil, or not, based on the
difference between the Virgin TBN and the TBN of the UAO, when the reality is the virgin TBN is not very important to the engine, certainly not as important as the base of the current used oil in the engine. Some people say change the oil when the TBN is 50% of virgin TBN, some say when it's a third, some say a quarter. Some state an actual number regardless of what the virgin TBN might be.
The TBN
in relation to the viscosity is what matters most, not TBN or viscosity alone, and certainly not TBN in relation to virgin TBN. The TBN is just a really easy number to point to and understand, and usually is a very good indicator of when the oil should be changed. With most oils, the TBN will be a very good indication of viscosity, and visa versa (acidity increases and viscosity increases), but, apparently, with this oil, the relationship isn't quite as linear, and works more like the heat index of a hot summer day, which is tied more to humidity than it is to temperature. You can have a relatively low TBN but still have a low level of viscosity, and visa versa.
The newer aluminum TDI engines can be less sensitive to acids because of the lower sulfur content in the fuel, and depending on whether or not you use a fuel additive like Power Service or Howes Meaner Cleaner that will both disperse and eliminate water (which causes oxidation in the oil and increases the corrosive potential of the acids found in the oil and thus destroys sheer protection rather quickly) and will boost the base ph with cleaning detergents which reduce the threat of acidity in the oil. With the higher fuel injection pressure and the EGR valves introducing massive amounts of soot into the mix, abrasives become more of a danger than the TBN. That's why filter changes between oil changes becomes so important.
But you can have a relatively low TBN, down to 1.0 or even below, but have low viscosity and low abrasives, and still be fine. It all depends on whether or not a particular diesel engine is sensitive to acid in the oil. Most aluminum engines, like the Sprinter (at least the old ones) don't seem as sensitive to oil acids than other engines. You can see it when you compare TBN to TAN (if your UOA has a TAN performed). Normally, you'd change the oil when the TBN and TAN meet up, but with newer oils, like the CJ-4 additive technology oils which start off with a lower TBN in the first place, and with biodiesel being in a lot of fuel not marked as biodiesel, the TAN number will often read artificially high (a molecule of sulfuric acid and a molecule of animal or vegetable fat will all have the same TAN number, but clearly one is more corrosive than the others). High pressure TDI aluminum engines like the one in the Sprinter (the old ones, anyway, and I would assume the new ones, too) are designed to run engine oil with a ph roughly the same as common kitchen vinegar or fresh squeezed lemon juice, anyway.
Of course, it's a differently engineered oil ..... it's specifically engineered to avoid poisoning emissions systems that come on more modern vehicles ....
I don't mean that it's engineered differently than 1960's oils, I mean it's engineered differently than other oils in the same 229.51 class. Mobil apparently took CJ-4 additive technology, or something, a step further with this oil to make additional increases in oil change intervals (which is what CJ-4 additive technology does in the first place).
As a consequence of that, it has less ability to counteract the contaminates that occur in engines, particularly diesel engines - it's a trade-off.
That is a reality - a fact - that occurs with any of the oils of this type - regardless of the refiner or blender.
Yep.
Yup
- I have no issue with the oil being used - it is what is spec'd and recommended - my issue is on extended drain intervals with
that particular oil ...
DO keep in mind that these oil change interval recommendations do not come from Mobil, but from VW and MB.
Difference might be, that we aren't talking about a pre-'07 Sprinter .... and the fact I have actually seen a number of UOA's (Used Oil Analyses) using this particular type of oil, used in these applications (diesel engines, '07 and later Sprinters specifically) .... and perhaps you haven't .....
I have seen very few UOA's of this oil. One, to be exact.
I stand by my statements .... I would be extremely leery of using this oil for anywhere near that long.
Regardless, I would remain merely cautiously optimistic.
As I understand it, the new Sprinter's with the OM 642 engine (V6) do not have quite the same ASSYST oil computer system as the older Sprinters do .... as near as I can tell the ASSYST counter count-down will not ever exceed the 10,000 mile recommended service interval ..... (like the '06 and earlier T1N's will)
True. Sort of. Far as I know, they all (North American models) come defaulted to 10,000 miles (or 15,000km depending on how you have it done). In Europe they are set as default to a higher number, or maybe you can choose, but I forget what it is (25,000km, I think, which would be 15,000 miles).
The older Sprinters come defaulted to use the ASSYST with a non-linear mileage countdown, meaning the oil quality sensor actually works, but it can be set to be strictly a mileage thing, just like the newer Sprinters. It can be set by a dealer, or by simply resetting the ASSYST with the three handed key on push buttons things like you normally do after an oil change, except you reset it,
and then immediately reset it again, before starting the engine. So, reset it, then reset it again, and it suddenly does a strict mileage countdown instead of factoring in the oil quality sensor. You need to visit a dealer (or possibly a DAD) to change it back to non-linear.
The new Sprinters are the same in reverse. A dealer
can program it to use the oil quality sensor, if they know how and are willing. But they all come defaulted to use linear mileage.
Things may have changed for the 2010 models, I have no idea.
But, I mentioned the ASSYST as a component in the confidence (or lack thereof) of the oil change intervals because I used several oil analyses at regular, specific intervals to check the accuracy and confidence of the ASSYST itself. Once the analyses confirmed the ASSYST, I then had confidence in the ASSYST alone without having to get regular oil analyses done. I brought it up to show that because the oil analyses and the ASSYST both confirmed the MB recommended 15,000 oil change interval of the 229.5 oil, and using that fact as an historical guide, it's the reason I would be cautiously optimistic (rather than blindly confident or extremely leery) with the seemingly exaggerated recommended intervals of the VW 507.00 oil.
Not having a functioning ASSYST with an oil quality sensor would certainly put a dent in the confidence lvel, as you'd be left with only the recommendation itself and the UOAs. But after a couple of changes, if the UOA indicated something close to the recommendation, the confidence level would go up. But functioning ASSYST or not, I'd still probably do just what I did when I got my Sprinter, and that's do an UOA at regular intervals until I was confident enough to pick a mileage number for the intervals. When I first got mine, I pulled samples religiously every 2500 miles for analysis. 4 or 5 times I sent samples to three different labs, just to check their accuracy (Blackstone and ANA were spot on with each other, and D-A Labs were inconsistent at times). I did that for the first three oil changes (and did it varying when and if I change the filter between oil changes). In all three cases, the UOA told me to change the oil at the same time the ASSYST did. With a new Sprinter and no functioning ASSYST, after about 3 oil changes and regular UOAs, you should be able to get a really good idea of max mileage for the future.
Perhaps piper1 will chime in here .... I believe he might have some relevant experience in regard to this matter ....
Sure hope so, not that I'm gonna get a new Sprinter any time soon, tho.
