whistling noise at high speed

[zhiyong80]

Hi,

I have been reading posts from this forum quite a bit before and after I acquired my 02 mountaineer awd v8. So thanks goes to everyone first.

Lately I noticed some sort of whistle like noise when I am driving at high speed (75MPH +), this usually happens during a hot sunny day.

https://www.dropbox.com/s/myu2gzikvgkv8ik/R20140607144455.mp3

Initially I thought it was AC related but it turned out not that. Also moving cargo carrier bars on the roof back and forth didn't help.

It doesn't happen during rainy days even when I drive at 80MPH+(just for testing purpose).

I am kind of out of ideas. Does anyone on this forum experience similar noise? I could use it as some kind of reminding when overspeed but sometimes it is annoying.

Cheer!

 

[Number4]

It's a common noise on the V8's though not usually specific to a certain speed. My Ex seems low on refridgerant. I'm starting to think it's the refridgerant cycling through the evaporator.

 

[zhiyong80]

It's a common noise on the V8's though not usually specific to a certain speed. My Ex seems low on refridgerant. I'm starting to think it's the refridgerant cycling through the evaporator.

Thanks for replying. But I am quite sure it is speed dependent. The speed has to be higher than 72-75. If it is lower than 70, there will never be that whistling noise. I tried quite a few times, if I slow down to just below 70MPH, then the noise will go away.

Also if I turn off AC, the same noise will still come up if it is sunny and speed is above 75. Kind of weird.

 

[name420420]

air leaking in a window? am not to sure it could be a lot of different things tbh. my back passenger window motor is shot so sometime's the window drops alittle and mine whistle's @ high speeds

 

[zhiyong80]

It has been a while since I posted the question. I'd like give it an update.

The truck died on me once in a parking lot, after a little research I decided to replace idle air control valve. So I fixed the problem, got better idle too. The unexpected consequence is, the whistle like noise at high speed also disappeared! It has been a few hundred miles, that noise never came back.

It hardly makes any sense. I would never associate that noise with an old dying idle air control valve. But believe it not, the problem is fixed.

 

[Number4]

It has been a while since I posted the question. I'd like give it an update.

The truck died on me once in a parking lot, after a little research I decided to replace idle air control valve. So I fixed the problem, got better idle too. The unexpected consequence is, the whistle like noise at high speed also disappeared! It has been a few hundred miles, that noise never came back.

It hardly makes any sense. I would never associate that noise with an old dying idle air control valve. But believe it not, the problem is fixed.

On the 02-03 models, the IAC Valve ha some kinda of black cap. People have stated that removing this cap would eliminate the noise.
Sounds like good news right?
Well the 04-05 doesn't have a IAC Valve and still has the whistling noise.

Glad it fixed yours. I just pretend I have a small turbo when mine whistles.

 

[zhiyong80]

On the 02-03 models, the IAC Valve ha some kinda of black cap. People have stated that removing this cap would eliminate the noise.
Sounds like good news right?
Well the 04-05 doesn't have a IAC Valve and still has the whistling noise.

Glad it fixed yours. I just pretend I have a small turbo when mine whistles.

Well, not strictly good news to me either. I actually kind of miss the whistle noise. Because it was so consistent, I relied on it as over speeding alarm, but now it is gone. That is how I noticed it. Apparently I was driving very fast, but that little whistle didn't come up. LOL