To close this, I put on a new water pump, tstat , tensioner and belt. I previously had an 82C tstat in before and now have a 92C one, so it runs warmer. It now gets toasty inside.I confirmed with my scangauge at 195-197 degrees. It took a little longer than expected, that underbelly shield is a real pain to deal with.

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2005 E320 CDI - Totaled