2007~2015: Need info on CX-9 engine part

[CmazdaX9]

The part on the valve cover, it’s on left side of cover in front of rad, it’s a round shape just to the left of last spark plug connector.

Anyone know what it's for?

Thanks!

 

[cx9 2008]

@CmazdaX9 You mean the engine cover grommet?

 

[Bronco Boy]

Oil filler cap.