My fan was clicking periodically, I sent it away and they said it was fine because it didn't want to click when they happened to test it... I since replaced the fan myself meaning I had to open the psu which voids the warranty...
Though, I guess most manufacturers would have said the same thing. Excapt Antec, who would have replaced it under good faith. (though they refuse to deal with my turquioise LED case fan).
edit: it took from friday to the monday after the following week till I had it back, which is good considering I shipped it before a weekend.