[MBZ] Leaky Glow Plug or Oil Pressure Sensor?

[John Peterson]

Hello folks, I'm getting what appears to be engine oil but smells like 
diesel around the area of my front most glow plug directly next to the oil 
sensor.  It appears to be coming from the glow plug, but I am not sure. 
Could be oil from the larger sensor next to the GP.

Should I try to retorque the glow plug, or replace it?  Do I need special 
tool to tighten GP?  Anyone had this?

John Peterson
1991 300D 2.5 74k miles
Kingston RI