I'd say anything from $2K to $3,500. Mileage isn't really a big factor. According to ebay, you have another 700,000 miles before you need a rebuild.
-Joe

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'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.