just replaced cambelt kit in my corsa but now there loud clicking noise?

If you're talking about the GM Corsa ie Opel/Vauxhall origin I used to work on these often. Some models had a modified tensioner and a modified bolt. Replacement of the original (hex) bolt resulted in the crankshaft pulley just touching the head of the bolt creating noise. Have a look to see how close the tensioner bolt is to the rim of the pulley. Also earlier models required pretensioning of the waterpump housing otherwise the tensioner can 'bottom out' and make noise. Hope this helps.

Kazza
July 2006