<VV> Squealing noise from engine compartment

[Joel McGregor]

Slipping belt?  My Fiero has the same symptoms except it does quit after it warms up or when you have a new really tight belt.  The alternator doesn't work until the squeal stops - that's how I know the belt is slipping.
Joel McGregor
>
> I have a squealing noise coming from my engine compartment. The noise is
> worse when I have my headlights on at night. At idle I cannot hear a
> squealing noise, but the alternator light is on. As I rev the engine the
> noise starts and progresses until about 2500 rpms then the squealing stops
> and the alternator light turns off. At about 4500 rpm at the squealing
> starts again and the alternator light turns on. Between 2500 rpm and 4500
> rpm, no squealing, no alternator light. When I drive the car during the day,
> no squealing, no alternator light.