Since owning my GT i've had an increasingly loud rattly noise coming from the alternator or crank pulley. I disconnected the alternator belt the other day and the noise stopped in the main, however I did note some rattles when easing off the throttle, and the crank pulley seemed to have some wobble to it.

 

I will have another look tonight as i'm eager to get this sorted as it's annoying me - is there a bearing that the crank pulley sits on that could be causing the noise or would it be a case of simply investigating and nipping up the screws holding it to the crank? Haven't really heard or read much about these failing before so it's an odd one on me!

only the crankshaft main bearings inside the engine

 

if you feel its coming from the bottom pully then either the 4 bolts arent tight , or the 19mm one has got loose and possibly ruined the keyway