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Your question was sent over to the Jag category so I will be taking over. You will need to use a 3/8" drive ratchet or belt tool to release the tensioner from the belt. The belt can be a pain to replace since there is not much room. The best way to do it is from underneath removing the wheel arch cover. Once the tensioner is released the belt will need to be twisted vertically and slide up and over the tensioner or you can loosen the 13mm bolt holding the tensioner to remove the belt.. Install it in the reverse of the removal.