[Aimers]

Found a rattle or knocking on top of the engine in a 2011 supercharge. Wondering how hard it would be to change the supercharge isolator myself

 

[OzXFR]

Lots of info about this over on the Yank forum: Jaguar Forums - Jaguar Enthusiasts Forum
Put simply it's hard as you have to take the whole supercharger off which is not a job for the unskilled.

 

[Aimers]

Ok thank you. About how much does it cost to fix

 

[OzXFR]

Ok thank you. About how much does it cost to fix

From memory around $1,000 US at an independent mechanics shop, more at a dealership.
The parts are not all that expensive, it's the labour that's the killer.