About 6 mos ago (give or take) I bought a 2000 Explorer (4L V-6, auto tranny, AC... ) from her 2nd oldest son. He always had it serviced (grease under his nails are foreign thoughts to him). The vehicle started making a loud (its not easy to describe) hum which SOUNDS like its coming from under the hood, but I've had a bear of a time tracking it. Its plenty loud, its not constant -conditions that affect it seem to be temperature (ambient) -I havent heard it when its cold out (well, I live in Florida, and by cold, I mean in the 60s ) but when the temp hits close to or above the '80s the noise is often there. Aircondition doesn't seem to affect it (on or off) and the noise will go away when you drive -seems to only make its noise while sitting, and tranny position doesn't appear to have an effect.
ANY ideas at all here?
Thanks!

 

Sounds like a dryer running??

 

That sounds like it might be the idle air control (IAC) valve. Does it affect the idle? High, maybe, then as the noise disappears the idle comes back to normal?
If so, you sound like you have the classic "IAC howl".
Search in this forum for the other articles on how to clean and test the IAC; cleaning might help, otherwise you need a new one. It's an easy, 10 minute job.
It's worthwhile replacing the gasket when you take the IAC off, even if only to clean it. Gaskets are only a couple bucks and vacuum leaks from the old gasket are another common cause of bad running and "check engine light" issues.
Let us know how you got on.

 

-Texan, no, cant say it sounds like a dryer... perhaps if the dryer had real deep issues...

-Allan sounds like the right word to use (HOWL) -Anyway, it always made me think of a valve howl or vibration (as in a valve not quite sealing, or something like that) -in any case, it does not seem to affect the idle or cause the engine to run rough (and doesn't cause the check-engine light to come on) but it certainly sounds like a good lead, and I'll definately try cleaning or even just replacing the gaskets (especially if its so inexpensive, its worth the try).
I certainly appreciate the replies and will post the results here.
TO THAT POINT, I'm off to Alabama in the morning, catching the end of deer hunting season (hey, the F-250diesel 4x4 was whining about not getting into the woods this season, so I figured it was time ) will return in the middle of next week, and try cleaning the IACv.
Thanks for the input and any other insight any of you may have.
See y'all in a week.
-NB

 

I would agree it was the IAC. To me it sounded like a dryer running when mine went.

 

That's exactly why I'm here. I have a 2001 Ford Explorer and my engine makes this whistle noise (sound like a dryer). Can anyone tell me If I'm having the same problem as NightBiker?

 

More than likely it's the IAC. It can sometimes be cleaned. It gets plugged with carbon and begins making the noise.

 

hey, leaving in a few mins. to alabama to hunt the very end of deer season, and wifey added one symptom to the problem (which in my humble opinion is likely consistent with the IACv -she says that the vehicle seems to run a little rich (smell), but says it does this all the time -odds that it could contribute to making the valve dirty (or be a cause of it being dirty? )?
anyway, when I get back, will clean or exchange it, and relay my results.
y'all have a safe week, and see y'all next week!