mikemover,

I agree with your conclusion, but I thought the other Mike was questioning whether or not gas cars can be made to last as long. Diesels last as long as they do because, as a class of machines, they were designed and built to be tools to make money with, which is not necessarily the design goal for most gas engined cars. The other aspects of Diesels, like the increases noise, vibration and odor/smoke make them less appealing to the typical consumer, so they have not been developed for that market. For most of us, that would seem to be a blessing as we apparently favor the industrial ruggedness and economy of operation over those other gas engine attributes.

Mercedes Diesels were developed for the taxi fleets around the world, and come from the same roots as the other industrial Diesels you cite as examples of how long lived they are. I think gasoline engines could be made equally robust, but due to their lower efficiency they are not the engine of choice for industrial applications. And the average consumer of gas engined automobiles is not interested in paying a premium for long life if all he is going to do is trade it in after two or three years of relatively light use. So they are generally not designed to the same standards for longevity and reliability.

There are some gas engines that, in the cars they come in, can do very well with the same rigorous care we give our Diesels. A few have noted examples. As far as the owners are concerned, these engines also provide superior life. Which is fine. The overall set of compromises embodied in these examples, however, is not the same as the set involved with a Diesel. They typically get poorer fuel economy and the cost of ownership over a decade or longer is not even close.

Every one of my old cars died or is dying from body rot after nearly twenty years, not engine failure. This is the same for gas powered and Diesel powered models by Mercedes. I can't say the same for other makes of cars I have owned - some have begun to fall apart and rust within 5 years. Anyway, the point is the intended use of the cars strongly influences the engineering goals, and Diesels are typically developed for a different market than gas engines. Hope this helps clarify my previous notes. Jim

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Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)