i have replaced oil tube ( oil seal ) sparkplug with new one witout adding any silicon and the same problem , should i add some silicon around oil seals? and what kind of silicon ? and how i add it ?

heres a pix

 

What car and engine?

There are also oil seals for the valve cover bolts.

 

honda civic si d16a9

 

When replacing a VC gasket i usually silicone anything that the gasket is touching, especially in the nooks and crannies such as corners, along with the spark plug holes.

 

Looks like a ZC engine, and it looks like the valve cover bolt seal in the center is where most of the moisture is. Silicone is not needed on those, just replace it