Engine noise after cam belt change

[milo900]

I've just changed the cam belt on my s8, got it all back together and fired it up to find it making a noise. I used the cam timing tool and followed the guide and on initial start up before everything was back together, it started ok. Slight noise initially that i put down to oil starvation but after a second, sounded normal. Now after putting the fan, rad etc back in, it sounds rough.
So yeah, any body got any ideas?
One thing I have noticed is after pulling the timing covers back off, it is slack at a couple of points on the belt, which seems weird.
Any advice appreciated guys.