I just purchased this 2006 F150 4x4 Extended Cab 4.6 Patriots edition truck.
It's been cold up here recently. When driving at certain low rpms I get a whining sound coming from the engine bay that sounds like a jet engine warming up or like a high pitched whistle. It goes away when decreasing or increasing the thottle. It's not a belt type squeal. Any idea what it may be?
Thanks!

 

Common & somewhat 'normal'.

Thousands of reported cases - very few actual remedies.

You can try to replace yer PS fluid with Amsoil ATF.

It may also be the dreaded alternator whine. Replacement is one fix.

Good Luck!

 

Thanks!
Does Ford reccomend using Amsoil synthetic for the power steering pump?

 

they recommend atf. Amsoil just works better.

 

I'm running Mobil 1 synthetic ATF in my PS - it's also better than the standard Mercon V.

 

Thanks! what amsoil atf spec.

 

The standard stuff.

http://www.amsoil.com/shop/by-produc...?code=ATFQT-EA

 

Great! Thanks for the info and link!

 

If it occurs in a very narrow rpm range, say between 2800-3200 rpm, and only when it's cold, you may also suspect the idler pulley bearing or the belt tensioner bearing. I've had heard it occur on a 2007 Crown Vic.