This engine noise is often misdiagnosed as an alternator or more commonly a power steering pump, a costly guess. In this video I show you how much it sounds like a power steering whine, how to test for it and then replace the faulty components. This affects the 4.6l and 5.4l in many different Ford vehicles, and as such I will be posting this procedure in many different sections as to not leave anyone out that may have this concern. This can be a very annoying noise but is such a simple fix.

 

That doesn't really sound like any of the PS pumps I've heard having issues. Most have sounded similar to this: