Hi Gang

New to this forum, but not new to working on cars. Well my wife's car is a 2004 Crossfire, and there seems to be a lot of noise coming from the Alternator. So I was wanting to take the tension off the serpentine belt so I could rotate the Alternator pulley by hand. Is there a secret size 6 point tamper proof torx/star bit that is in the center of the Idler pulley.

All the sizes I have are either too small or too big, what size is that.? I just want to take the tension off the belt, not remove the Idler Pulley.

Thanx....Gunny