Ducato 2011 2.3, am changing the timing belt, I note that the timing belt kits (Fiat and aftermarket) include a new bolt for idler pulley (and idler pulley on aux drive belts), but not the tensioner pulley, this would seem to indicate that the idler pulley's are held on by stretch bolts, but tensioner pulley is standard flanged bolt, the markings on the tensioner pulley are so badly impressed it's hard to tell what it is. So bearing in mind previous threads on this subject, does anyone know for certain if this bolt needs changing?