Intermittent "WOOOOO" noise from under hood.

[ThreeJs]

I've had this happen a few times over the past year or so. Normally only happens when I'm driving in traffic and the temps are usually warmer. Only at idle and goes away immediately when throttle is applied then goes away. Happened once during prolonged idling in park. Drives normally otherwise.
1996 4.0 OHV, 144K miles, all stock, new air filter.

 

[mcarcher10]

I have also encountered this the past 2 summers with my truck. I have narrowed the noise down to under/around the air filter. Only happens on hot days, and it drones on louder during idle, and seems to lessen and then stop when driving. I am curious to see what it might be. Air filter and air flow sensor are both clean btw.

 

[sgully67]

The noise is caused by the air resonating in the intake tract. Can usually be corrected by replacing the IAC valve.

 

[swshawaii]

^ Or try cleaning first.

How to: IAC valve cleaning thread (w/pics)
http://www.explorerforum.com/forums/showthread.php?t=84220

If replacing, the OEM part is preferred.

 

[ThreeJs]

There seems to be no ill effects while driving so I will just let it be for now.
If it becomes troublesome I will try replacing the IAC,

 

[fast_dave]

There seems to be no ill effects while driving so I will just let it be for now.
If it becomes troublesome I will try replacing the IAC,

Just saying - when the IAC fails, you will not be able to idle

If you don't service & clean them regularly, they're a 50-60,000 mile replacement item.

swshawaii turned you on to the definitive IAC Valve thread

YMMV -

 

[ThreeJs]

I work in auto parts commercial sales. Getting the part at a great price isn't a problem.
So far, it has been rare enough that I'll let it go for a while.

 

[lobo411]

Seems like a common problem with older Fords. Had the same issue on my 96 explorer and two late 80s Tauruses as well.

 

[mcarcher10]

Thank you swshawaii for that awesome link! Can wait to give it a try this weekend.

 

[swshawaii]

Agree it's an excellent "how to" and there's a lot more of them in the "Under the Hood" sub forum sticky's. Check them out.

Instead of using electrical or MAF cleaner, I found throttle body or carb cleaner better for removing carbon or varnish deposits.

 

[wagonmaster69]

MOOSE whistle you got the dreaded moose whistle.
Yea change the IAC valve like swshawaii said and it goes away.
Not hard to do go to rockauto.com good prices.

 

[ThreeJs]

went ahead and ordered a new IAC through work. For $21 I figure it's no big deal

 

[Turdle]

Kicking up an old thread


http://www.explorerforum.com/forums/showthread.php?t=85293

 

[swshawaii]

Kicking up an old thread

http://www.explorerforum.com/forums/showthread.php?t=85293

Too funny! More amazing is it's spelled wrong in both threads. Isn't it WHOOO? LMAO

 

[koda2000]

One of my 2000 Mountaineers did this. Cleaned the IAC (twice) with no improvement. Replace the IAC with a new $20 Chinese one off eBay. No more noise.

 

[ThreeJs]

link doesn't come up for me?
Here's what I get:
Http/1.1 Service Unavailable

 

[ThreeJs]

Too funny! More amazing is it's spelled wrong in both threads. Isn't it WHOOO? LMAO

It's written out phonetically to try to impart the actual sound the best way possible. It is more of a woo sound..like woo-woo. Not a whoo sound like whoo-whoo, like owls.

 

[ThreeJs]

Got home today. 115* and I had the moose call. Pulled off the black cap and it stopped. Capped it with my finger and it was even louder. I swapped out the IAC with the BWD replacement and ...silence.
Problem solved...