I doubt a turbo rebuild would help, since that is mainly to cure oil loss. If the compressor wheel spins easy and the shaft feels tight (no wobble), and you have no oil loss, the turbo would seem fine. How it performs is answered by plumbing in a boost gage. That takes 5 min for a temp setup. Not sure why anybody would even ask here about performance without having done that first.

The OM617 has intake and exhaust on the same side, which restricts air-flow, compared to a cross-flow design like the later M-B diesels. Still, it performs fairly well at high-rpm compared to most other vintage diesel engines.

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