Not necessarily, and the severity/frequency of the noise will vary greatly with engine speed when the engine is not under load. Diagnosis based on a sound clip from a mobile is obviously difficult, but I wouldn't have mentioned it if I didn't think it was a real possibility. If it is a sharp, metallic, almost random rat-a-tat-tat, tat-a-tat-tat, tat-tat noise, then you should be worried, and really shouldn't drive it until it's diagnosed properly. Sorry to sound like the Fifth Horseman; I really hope it's not, for your (bank accounts') sake.
Edit: I've just listened to the clip again (several times), and the more I hear it, the worse it sounds...
Last edited by FoxtrotOscar; 06-11-11 at 21:42.