It's not a turbo, it's a supercharger aka Kompressor. AFAIK, it has it's own sealed oil supply and is not fed by the engine. The grinding noise could have been clutch or the eaton, but the dealer would replace both I assume. I have read several posts about people changing the oil in the supercharger, but haven't seen a procedure anywhere.

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2000 C230 Kompressor "Frosty"

2007 PT Cruiser
2001 VW TDI Beetle
1999 Landrover Discovery II
1971 Corvette

Gone: 97 Cabrio, 83 240D, 93 VW Eurovan, 95 Volvo 850, 93 Chevy Astro Van, 77 VW Bus, 99 VW Jetta, 74 VW Bus