Thanks to all for the feedback. Gilly -- what I see is definately the black, gunky sludge, not the milky white stuff you refer to. The ML does see cold on winter Colorado mountaineering trips, but 98% of the time, I am in relatively warm Dallas. Steve -- My understanding of the MB suit is the same as Lebenz and I would also be interested in your reasoning that it may not apply to my situation.

I treat my ML like my favorite pet, but I also use it's features as they should be (off road, etc.). I have had the oil analyzed at Blackstone Labs at every change and they are now seeing particulates that indicate bearing wear. They also noted the last sample exhibited some breakdown characteristics. I just sent them another sample with a shortened service life (6K) to better monitor the situation. Prior two FSS governed changes were 16K and 20K miles. This longer period is due to FSS interval increasing every time the oil level needs to be topped up (fresh oil making the sensor think things are cleaner).

My opinion at this time is no matter what oil you use, your interval should not exceed 10K, regardless of the FSS indication. My former Chevy C1500 with a 350 saw Mobil1 for 85K miles, stayed clean as a whistle and never needed oil added with 9K intervals except at every 3K, I changed the filter and added a quart due to filter change. I am considering a similar routine with the ML.