squeking

[Mayhem_J30]

i believe this might be related to my altenator pulley going bad. if i turn on the headlights during idle a squeking noise comes from the motor. i can almost pinpoint the noise coming from either one of the belts or the altenator. I believe it is coming from the passenger side too...where the alt is. Always hard to pinpoint noises though. Does this sound like the alt pulley going bad? The belts are all at the correct tension specs. Even though the belts appear to be at the right tensions...is it possible one is TOO tight..since measuring belt tension isn't an exact science?The altenator is original with 120+K miles. I haven't had any light dimming problems yet...

[DAEDALUS]

I've never heard of a too-tight belt causing a squeaking. It could be the alternator bearing going bad. A too-tight belt would cause or hasten this to happen. To verify it's the belt or the component, remove the belt temporarily and run the car on a good battery for a bit. Turn the alternator by hand and see if it feels smooth. If not, it's most likely the bearing.

[Eswift]

i would try loosening the acc. belts just a little bit. you might be experiencing some kind of weird resonance at the specific idle level required by the increased current load imposed by turning on the headlights. ( i had a similar situation on my old Z31 and that worked)