Need a help to identify a part

[astamir]

Hi guys
I hope you all doing well
Opened the engine plastic top cover yeasterday to clean it a bit on w211 320cdi and noticed either oil or desel leak from a sensor on top end cover picture attached
Does anyone know what's this one for?
Thanks

 

[astamir]

It's on a top end closer to the back end of the engine

 

[AndyPCD]

It looks like a camshaft position sensor.

 

[Terry_]

It's the camshaft position sensor

 

[astamir]

Thanks guys put the o ring sealer or what it's called to stop the leak from there. Looks ok
Btw what does it do is the leak from there would affect the engine performance ?
Thanks again

 

[astamir]

Sorry wanted to ask putting the o ring made it a bit out by 1mm would it affect the engine performance?
Thanks