That looks like the block drain plug on my M111. You could try to just tighten it. Or, remove it as tom suggests, clean it and then re install. I'm not sure what the plug seats against to seal, not sure if teflon would seal it or not.

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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