Technical crank vibration dampener replacement

[kevinski]

Hi all I hope that someone could help me. I have fiat marea 2001 1.9 jtd.After hearing noises from the engine I discovered the crank vibration dampener lying in the engine compartment on the plastic splash guard. The rubber ring had perished and the wheel just came off! I believe it to be number 8 in this this link (http://i48.photobucket.com/albums/f205/Bravo_Pro/engine1.jpg). I was wondering how difficult is it to replace? Any advice would be very much appreciated.