I know there have been a few posts about setting the Assyst system for the fully synthetic oil after a service but having just had my 2004 E320 CDI serviced thought I'd share my experience. The car was serviced a few days ago and I wanted to check that as Mobil-1 229.51 was used it was reflected on the Assyst system. I went through loads of posts to find how I'd got into this in the past and finally remembered that I found the sequence different to what I'd seen posted. Car serviced at 72,915 by Mercedes dealer D+ Oil & filters Poly belt check Combination filter Noted items:- Pads 75% disks 25.5 (min 25.4) (Quote to replace both £460) NS diff seal weaping (Quote £348) NSF trust arm outer rubber split (Quote £269) I did ask if the rubber could be replaced but it comes as a complete unit, the joint is not worn as so it might as well be left until wear is detected and then replaced. Rear springs surface rust (Quote £327) Can't say that this bothers me and will simply spray WD40 on them when I get a chance. So assyst, for my car the way into the service settings was as follows:- > Turn the ignition key to the 1st setting. > Set the display to the outside temperatue > Press trip 3 times > Using the steering wheel buttons:- > Down arrow to "Service Menu" > - button to move to "Addit Work" select using page down button > - button to select "Item 13" select using page down button > Oil setting is now displayed Standard or 229.5 (use - button to move highlight) > Press page down button to save setting (important or it's not saved ) When you 1st go into the service menu it will show miles to next service and days, mine was +9,150 miles and +730 days. After changing to the correct oil it increased to +12,427. The mileage from my last service was 12,557 (again I corrected the oil setting after the car came back) so it's about right. So with a current mileage of 73,113 I'm expecting to need the next service at 85,540 some 3,000 more than I'd have originally got. The dealer will be contacting me for service feedback and I'll point this out to them when they do. I had the same issue with Tony Purslow for the last service the dealers just don't bother to set the correct oil. Mind you as the car then calls for an earlier service you do wonder if this is deliberate? Anyway, hope this helps others.