Wierd Noises???

My 03' Hyndai Elentra makes a clicking sound like if a piston is blown but it's not that I'm guessing the alternator might be loose because it sounds like it needs to be tightened. Any help would be nice because i'm new to the car scene and I need to know where the alternator is....any help would be appriciated. Thanks

Oh yeah I forgot to mention that when I let it Idle it makes the noise also

1st check the oil.2nd call the dealer

i dont think it has anything with the oil.....something is loose......i think maybe it may be the auto tranny