I've got a 2003 f150 supercrew with a 5.4 in it. I have a whine coming from the engine bay. I thought it was the powersteering pump and changed that and that wasn't it. I'm thinking its the idler or tensioner pully. I've ruled out the alternator by wrapping rags around it and it didn't dampen the sound any. What do you guys think?

 

you need to take the fan belt off and spin each component individually. You might even start the motor and run 30 seconds to prove that removing the belt solves the problem.. Prior to removal, i think i would clean the belt or just spray some water on it while running (minor amount) to see if the noise changes pitch. Could be just the belt and not the pulleys ?

 

It's a consistent whine it does get a little louder when you give it gas. I've watched it when I gave it alittle gas and the tensioner pulley moves and gets pressure on it and the noise increases. I'm gonna take the belt off and run it to make sure it's a pulley tomorrow. Thank for the advise!

 

I would bet on the idler pulley, sounds like u have a small turbo whine when it does it. Just changed mine last week, same truck '03 supercrew 5.4.

 

Yep it does sound like a turbo whine and it's just alittle Then it gets alittle louder and then just whines consistently enough to drive me crazy!

 

Well I got a tensioner pulley before I came home tonight. I took belt loose and everything was quiet. Pulled the tensioner and then put belt back on fired it up and quite as can be. The tensioner pulley was producing the whine like what you hear from the power steering pump when it is going bad. Thanks for all the help and opinions!