Hey Guys,
This is only my second post here, but since I own a 535i, I did quite a bit of research on oil and OCI and think I may be able to offer "some" insight:
- PN 07510002545 is in fact an old PN, and it was superceded by PN 07510017866 which is indeed the BMW synthetic 5W30. BMW, at least in the US, only offers this oil for all gasoline engines
- It seems in countries outside the US, BMW specifies an LL-04 oil for the X35i (N54 engine) but we cannot use it in the US due to differences in fuel quality and a richer fuel injection. I found no data as to whether this oil mitigates fuel dilution issues or high temperature issues
- Forums (not only BITOG) do show some data of lousy UOA after 1000 mi oil changes, but at the same time, I have seen several UOA reports of owners of 335i with OCI of 4000, 6000 and 7000 whose data looked pretty good. I have even found 1 report where a guy had done a 14kmi OCI and his oil was not great but not as terrible as one might think (the oil had thickened to a 15W40 equivalent and only had 2% TBN)
Like other owners I concluded the following:
- BMW's recommendation of 15kmi OCI is more than optimistic, so for anyone keeping the car long term, a safe bet is to do a shorter OCI
- That shorter OCI could be as short as 1 to 2kmi for someone driving in "severe" conditions (cold start, numerous short trips, high power acceleration, tracking) and as long as the full OCI (for someone driving a very long commute for example)
- There is no recent data that I have seen lately justifying the concern over fuel dilution. There was a lot of talk about 2007 and early 2008 models, but since then, every UOA I have pulled showed no sign of massive fuel dilution. I am in fact wonderring if the fuel map has been altered by BMW in recent versions of the DME
- Everyone has seen that these engines run hot (from 240 to 280F in every day applications), however, similarly to the fuel dilution, all the recent UOA I have seen showed nothing worse than 1 grade worse of shearing or 2 grades of thickening for the cold viscosity measurement
As far as I am concerned, I did an oil change at 2400mi (break-in), will do one at 6500mi with a UOA, and then I will get a free one at 1 year and about 10,500mi. I will do a second UOA then and determine how frequently I need to change oil. I have also purchased some Motul X-Max 5W40 for summer application