Good Day,Had on my 2007 XK8 Alternator go out ,So i order one ,plus a Belt Tensioner ,install the Alternator and to tensioner and tried to reinstall my Serpentine belt but now have to much play ,On removing the belt us the tool bar remove the belt remove the tensioner and install the Alt ,but i think i have the belt wrong want on line look at the patter but is to loose anyone can send me a correct diagram for a 2007 XK8 not a R .Thank you ,By the way this form is great i have learned a lot by reading it a ,We have five jag now , two 1998 xj8 ,1999 xk8 r cab,1999 xj8 VP and now this 2007 xk8

 

I assume that you are working on the 4.2 Litre engine. If my assumption is correct you will find the diagram for routing the serpentine belt below. If it isn't the 4.2 get back to me and i will post the 5.0 diagram.

For future reference you will get a quicker response if you post in the X150 forum. That is the model designation for your 2007 XK8.