I have a A6 Lim. quat. 2.8 142KW /EG2 A5 Build Date 12/97. (This is a direct copy from my Audi Vehicle Data booklet.) 153,000km

on starting the car as the engine catches and fires there is a loud clicking noise till the ignition key is released. I thought this was the starter motor and my mechanic agreed. The starter motor was replaced. The noise did not go away. He now thinks that it is the flexi-plate between the engine and auto gearbox, it maybe cracked. Has anyone heard or experienced this?