I think you guys should really check the all the belt pulley.... bearings might have worned out, the belt might be missaligned already so it makes sound when it turns... my experience... the whole pulley fell out...first time (last year) was the pulley nut locking the bracket broke (dunno why... too hot gua..) then last week the pulley came off again, this time was the bearings.... took me whole hour just to take the pulley out (it was sitting between the belts and engine was hot) have to cut off the perfectly good compressor belt (luckily I've got the tools readied in my car) now running without aircond :( check it.... don't ignore it.... and don't high rev... the more you rev when it's making noise, the faster it breaks down... (belt turns faster mahh...) good luck.
