Z06 Accessory Drive noise-what's failing?

[dennym]

Coming back from AutoX yesterday. Heard a squeal/whine that varied with engine speed as I took the ramp on to interstate. Stopped. Saw what I thought was a screw backed out about 3/4" from the idler pully below the alternator. A buddy released tension on the belt. I tried to screw it in ... found that it's just a plastic plug and just pushed it in ... pulley seemed ok, but I thought perhaps the bearing was going. What to do ???? started it up ... no noise ... went down the road. couple of times on the road, squeal picked up. Stopped, checked ... everything seemed ok. Did 190 miles this way easy ... now I'm wondering ... (I don't have a shop manual) if the bell-shaped thing --- is that a harmonic balancer??? might be going out. any help here? Search turned up nothing.
TIA.

 

[c4c5specialist]

HI there,
I would definately look at your harmonic balancer. If it has any visible wobbling, then you may need to have it replaced.
There is NO GM specification for the runout of the balancer.
Let us know how you make out, c4c5