Repair-It

This was easy. Jack car up, remove main under-engine cover and the drain plug is exposed. 13mm I think. Drain oil. It takes a while to drain, even hot. This surprised me but not a big deal. On top, the oil filter housing takes a 27mm unlike my other cars which take a normal size oil filter wrench. It also looks like they simplified the design because rather than a big long skewer and a bunch of O-rings, the filter sits in the filter housing, and then slides over the skewer which is now built into the filter adapter. The only O-ring to worry about is for the filter housing.

OEM oil filter. I bought a Hengst.
It was a year overdue for an A service and based on the 8/2020 date on the filter, this checks out. I reset everything. It's the same procedure as my S550. Ignition in "Position 1" (tap button without foot on brake), press and hold call answer + OK button. It opens a menu and you can drill down into the system to reset things.
I believe I have now completed the 100,000 service, in segments. A shade under 99k. I did peek into the timing cover again with a flashlight and it looks totally spotless. So I guess 10k oil changes doesn't totally sludge everything.

About 4,300 miles later it asked me to add a quart. I have not done so yet but it is very close to the end of the season...

Oil change @ 103,974. 8.5L of Molygen 5W-40. Will post Blackstone results when I receive them. Nothing unusual happened during the oil change otherwise. I did notice the oil level seemed to be halfway on the dipstick between min and max. I thought that might be normal but I checked it after changing yesterday and it was all the way at max. I am not sure what the correct oil level actually is. I went by the computer when it said to add last season, and never really verified anything on the dipstick.

While I was filling I noticed I have a timing chain tensioner. I don't know if this is the latest one but my understanding is my car was not built with this. Will post more things... viewtopic.php?p=23606#p23606

A month later I finally got my Blackstone analysis back.

Notes: No issues, really. Couldn't really ask for better results. However, the MB forum pointed out that the high calcium is indicative of not being API SP (which is true) and that can impact LSPI (low speed pre-ignition). While my viscosity actually looks pretty good, I am still seriously considering a switch to Motul 8100 5W-50. My butt dyno says my cam phasers need more oil pressure as the oil gets hot because there is some very solid drivability at the 100-130F oil temp range, but it slowly goes away as it moves to operating temp. The best I can describe is surgey and when hot it feels more like the oil pressure solenoid is plugged in again (which is why I am going with viscosity loss as the culprit, plus tired original adjusters I'm sure). At the very least I guess I can confirm that it is NOT due to oil viscosity.