Scanned some of the posts and didn't see this, but my understanding of one of the primary reasons for Diesel longevity vs. sparkers is that a when a gasser begins to burn oil from wear, the plugs foul and in addition to operational problems, starting becomes very difficult. With a Diesel at the same wear point, it functions fine with crankcase oil simply serving as an auxillary fuel source. At least as long as it is replenished as part of "refueling" and you have enough compression to get it running you can go forever.

__________________
2008 GL320CDI 6K
1970 280SL 112K
1982 240D 210K (Sold)
1973 220D 220K (Sold)
1967 200D 160K (Sold)
1992 400E 139K (Sold)
1988 300E 148K (Sold)
1987 300D 257K (Sold)
1991 300E 108K (Sold)
1987 300E 131K (Sold)
1978 300D TMU (Sold)
1980 300D TMU (Sold)
MBCA Member