I need a new fuel cap for my 1.7 TD Fiorino as the inner mechanism has just crumbled due to age and being soaked with diesel. The barrel/key still works fine. Went to the fiat dealer, they say no longer available. Apparently the cap is unique to the Fiorino. Anyone got any idea where I can get one? I don't need the lock barrel I have it ready to fit into the new cap. Has anyone tried using a cap off a newer Fiat with any success?