it's not exactly a squeal .. more like a rattle , but only at certain RPM's .. the belt is new (motorcraft) .. i replaced the water pump and power steering about 2 months ago .. I have dual alternators so in addition to the standard tensioner ... I also have a secondary idler pulley down by the lower alt ..

it SOUNDED like it was coming from that idler .. so I've now also replaced the tensioner and idlers .. all Motorcraft ..

That helped a LITTLE ..but it's still there.. i took the belt off and hand spun the alts to see if I could hear anything .. the lower alt DID have a bit of a noise on spinning ...

Could it be the alternator making that noise ? would it only last through certain RPM's and then go away after say 1200 RPMs ? .. any other ideas ???

 

anybody ????

 

Could be, have you tried running a single alt belt and eliminating the second alt out of the question? Not sure if the extra pullies would be in the way of routing a single alt belt or not though. I thought someone decided to only run one due to a problem with the second a while back, but don't recall if they had to take anything off or just swap in a shorter belt.