Whistling noise in cold weather from under hood
 

Ok, I have posted this before with no replies.. When the air gets cold I hear a whistling noise.. Kind of like a steam whistle coming from under the hood.. It is in sync with and changes tone with the acceleration and gear changing. It is not a window seal on any type of wind deflection.. The colder the air the more frequent the noise and it gets really annoying on the highway.. Ofcourse I do alot of highway driving so it drives me insane.. I will be cruising along and it starts whistling then if I let off the gas it goes away. The truck has done this since new but ofcourse I could never get it to do it for a mechanic so I am stuck with this problem out of warranty.. just wondering if anyone had the problem or knows what it could be? I would think it is something to do with the air box?? Don't know though..

-R.

Hi, Mine just started with this SAME damn problem this morning...it stopped though i was thinking maybe the belts?
If you get any answers let me know..Thanks :P

...Welcome tbell73, to Ford Truck Enthusiasts!

Enjoy FTE....see you on the boards.:-X22

With the hood open, and moving the throttle cable, you hear the noise change?
You can't pinpoint it? Make a stethoscope with a piece of garden hose, or broom handle....be careful.

I had a similar problem on mine. It started after installing a K&N open filter. If I tapped the thottle, it would go away momentarily. After replacing the idle air control valve, it went away. Had to have it replaced again last year and the dealer said it was a common occurence with that air filter installed. You can change it yourself, but it will cause the check engine light to come on and you'll have to get someone to reset it.

My truck is all stock with the ford air filter.. I am leaning towards the idler pulley mentioned in the other post.

-R.

On my explorer, there is a tube coming off the air intake hose and I think runs to the valve cover. I get the whistle when the tube isn't sealing in the air intake hose.