I had to replace the Oil sender switch on mine. I just pulled it out off a gasser engine at a Junkyard and put it on. The O-ring was still good so I did not changed it. Pretty simple to do.

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06 MB E320 CDI 123k miles
14 Sienna (wife's DD) 36k miles
11 GL350 Bluetec 136k (Sold)
96 E300; 292k+ miles (Donated)
11 Sprinter 22K+ miles (Sold)