Sometime last year I replaced the cam chain in my GF's coupe as it had a bottom crank seal leak anyway and thought it would be good to get it done before it breaks. The car has covered less then 60k and since we bought it, it has always had this kind of rap, rap, rap sound at idle. It doesn't go away at all as the engine warms up and is there all the time at idle, I had hoped that the chain and resultant oil change would cure this problem but it is still there. I then checked the exhaust mani bolts, one was slightly loose but nothing major. What else is it likely to be? I am experienced with cars especially VX's and have never heard this sound before it is not a tappet sound nor is it a knock, as said the best description is a rap, rap, rap sound. The only thing I can supect is the drive belt as this was not replaced with the chain, I am doing it this weekend as it has started slipping, maybe this will cure it. What sort of sound does a leaking flexi make? I have not yet checked this part either.