Ticking/Clicking from bottom left of imac

My 20" iMac, which is less than a month old, just started making this sound yesterday. I'm planning to call tech support.

I can't remember where I read it but it could be a loose connector ribbon lightly hitting the fan. Probably a good idea to have it looked at.

Exactly the same. Ran fan utility and the noise disappears when doubling the cpu fan for a minute or so before returning to normal. However, it returns after a day or so. More recently it returns more and more quickly. The temporary cpu fan speed seems to 'unstick' a fan misalignment or something.

I have taken it back (as advised by Apple tech support staff) to a dealer twice but they have not been able to hear the noise in their workshop. On the first occasion I could not hear it when I took the iMac back. After a couple of days it returned. Second time it was still there when I bought it home. Presumably their worksop noise covers up the noise.

It is on the verge of driving me mad but I have no solution.

Ok, I've started to notice it as well. Though it seems to be one of those problems that only gets annoying when you focus your attention on it. I only noticed it briefly before deciding to investigate further. Mine seems really faint. I have to put my ear at a certain angle close towards the machine before I can hear it consistently.

The annoying thing with these kind of problems is getting the tech to acknowledge it's existence. For me it's not worth trouble. Really depends on how annoying you find the noise. (maybe your particular machine is producing a more apparent noise)

I don't think it going to lead to anything breaking it's more a matter of personal tolerance.