All cars require maintenance, but if not driving it and just parked outdoors in PA then it will deteriorate, so no sense keeping it unless you want to maintain it as a museum piece. I have heard many people use Bringatrailer, but don't know that a M-B diesel fits as more are looking for muscle-cars and pickups. Also look into coparts auction, but think you must deliver the car to one of their yards. This site has the most who appreciate the cars, but most also have enough cars already.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans