Thanks for the replies. While i'm positive that mobil 1 (in any grade) is NOT an acceptable diesel oil, I wasn't aware that its not approved for MB gassers....? Almost ALL of the dealerships use mobil1 for their oil changes.
For those fellow dieselers, its been widely recognized that Amsoils series 3000 or mobil's delvac 1 are far and above the leaders in synthetic diesel oils. Rotella or Delo simply aren't as high of quality, although both are way better than something CF like mobil1 or syncrap.
For those searching, it will be harder to find delvac 1. The easy answer is buy it online.I bought a case of 4 gallons for $82 at
www.avlube.com
and they were delivered that week to my door. Seems easier even than a trip to wal-mart(select wal-marts carry delvac1) Be sure not to get Delvac 1300 or anything other than Delvac 1.
I've previously been running the amsoil series 3k, however since my TDI uses 5w-40, i'm switching both to Delvac1. I had an oil analysis done on my 606 engine with 35k on the car, and 5700 miles on the oil. Results were pretty good, but the first analysis is only good for a baseline. Changed the oil at that point, so I can't wait to sample again at 5700, and 10,000. I'm guessing with delvac1 or amsoil that the correct drain interval is around 10k miles. Results are available on this forum if you search for my name and oil analysis. Pretty impressive filtration from the factory, after 5700 miles I had less than 1% soot.
PS Loudapache - an oil analysis at 5000 miles is relatively worthless, as the oil supplied from the factory varies, as well as the high level of wear metals present from break-in.