What Is This?
 

This is a picture of the reman left head for my 2004 5.4l 3v on my rebuilt block but for the life of me I cannot seem to figure out what goes on the gear type bolt to the left of the reservoir bracket bolt.

https://cimg2.ibsrv.net/gimg/www.f15...85a9fe4f9a.gif


Any ideas? I don't think it's my power steering pump. I am at my wits end on figuring out what it is.

Thanks,

Ken