My dad's '99 limited X with the 5.0 makes a really odd sound. Whenever the engine is running, a loud whining occurs, though it is not the alternator because he just replaced it with a new one and it still makes the noise. The whine sounds like it's coming from there, but I wouldn't think the new alternator would make that noise. Also no vacuum leaks or broken hoses, it's just a whistle from the vicinity of the alternator. Any ideas?

Check the idler pully, it might be going bad. Also, a IAC motor on the way out will make that sound.

Ya, check the pulley. Had the exact same prob, thought it sounded like the alternator for sure. Picked up new pulley at ford for $30, no more whine.http://www.fadzter.com/smilies/spotman.gif

Ted

Same here, was an easy fix.

Thanks guys, we'll check it out!

Before we take anything apart, is it the idler pulley on the top or the bottom?

Idler pully is on top of the engine to the right of the alternator. It's between the alternator and the AC compressor pullly.

We replaced the top idler, but the noise is still there. You guys were definitely right though, it was shot:eek: ! Do you all think the IAC could be the culprit, or maybe the accessory drive belt? No detectable performance loss from this noise, just kind of annoying. Thanks for the suggestions!

Check the pully at the bottom. That's the one that was making noise for me.

Ted

Here's a couple of pics:
http://www.imagestation.com/picture/sraid61/p637ad942d03a1b38e023d59c4c8acf2c/fc2c8e68.jpg

Idler pulley:
http://www.imagestation.com/picture/sraid61/p143d8fdcdc8b2bd1f819666e039bcc5d/fc2c8e65.jpg

tas98xlt-
great pics! Thanks alot, because my dad and I were beginning to wonder what else it could be. We'll replace it tonight and I'll get back to you. Thank you!

It's silent and what a world of difference!! Thank you all for your suggestions. You guys were dead on.
:D

NP! Glad it worked.

Ted:cool: