I'm referring to the M104 engine...probably should have made that clear earlier...

...so now I'm confused? Mine screws on with the hollow end down (solid end up). So when loosening it, am I in for a mess or not?

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car