Whistle under hood

[KKM]

I have tried telling my customers for quite some time that the noise has always been there, you just hear it more with an open element air filter.

I have traced the noise to two seperate sources; One being a hanging and dirty IAC valve, which you seem to have addressed. Two being harmonics in the crankcase vent line. Try restricting the vent line slightly, with a hose clamp or zip tie from it's current diameter and you should hear a change or elimination of the noise.

On other Ford models, the noise has been quite bad. They resorted to installing a large foam sleeve over the vent line as factory standard on the 95-97 2.3L Ranger because it was so bad.

 

[Stic-o]

tha whistle go.....

WOO! WOOOO!!

 

[o6tnineo]

3-4 years later.....

I recently installed a kkm kit on an '05 explorer and that whistle is there at 2,000 - 2,500 rpms. Just so you know, the whistle was there with the stock setup. Albeit barely audible.

It is not the IAC.... I had a 96 X that suffered the dreaded HUMMMMMMM.... A new IAC unit fixed that problem. This is definently more of a whistle as described by others in this thread.

If it is harmonics, I'm surprised there is not a simple way to fix this. (maybe restricting the passageway with something).

Has anybody found a solution. It is really annoying.

 

[ecclesj]

My stock '04 4.0L Limited is doing the exact same thing, whistle between 1800-2400 rpm.

I've only had the vehicle for two weeks and found the whistling odd for a vehicle with only 42000 miles.

My wife had a good suggestion: Pretend it's a turbo.

 

[Gus Gorilla]

I'm bringing this thread back from the dead. I just put a K&N FIPK system on my 01 Sport Trac. I have this mystery whistle problem and need a fix. Has anybody sucessfully beaten the whistle?

 

[Donner]

I'm convinced that the whistle is the alternator's final scream... I'm getting another put in tomoro - rats.