Went and drove it at lunch (1 degree out) after the truck sitting for about 5 hours outside. I hear the whistle at 1900-2000 RPMs and only for a second. I could only get it to make the whistle under acceleration. It sounds like it is coming from the divers side of the engine compartment up by the dash. Is the PCV in that area?

We did get snow last night, and the previous times i heard this we had snow. Maybe there is some corilation with moisture and temperature?

Well if that's the case, then I doubt there is a fix at all for this.

No correlation with moisture. We haven't had any snow and I've got this issue. This is everyone with an F150 in cold weather who is accelerating though.

Duke

I've heard the whistling sound on occasion, but I don't think the noise from my truck is quite as bad as the sound you describe. However, I had noticed a knocking/thumping noise that seemed to be getting louder over the last several months. (This noise is best described as similar to the sound made by a distant helicopter.) I only heard this noise under acceleration--if I took my foot off the gas, it disappeared.

Based on information I read in another thread, I checked the air intake tube where it joins the driver's side fenderwell. Although the intake appeared to be securely fastened to the fenderwell, I found that the assembly can be moved somewhat. Also, the plastic circular piece that surrounds the point where the intake enters the fenderwell can be moved as well. I adjusted both the intake and the plastic ring to ensure they were as secure as I could possibly make them.

This morning (temps around 25 degrees), I didn't hear the whistling noise, and the knocking sound I described above was greatly reduced.

It's my guess that the whistling and the knocking/thumping noises are related to the intake connection at the fenderwell. Try adjusting this connection and see if the noise subsides.

Good luck!

when I had my 04 F150, it made the same sounf in cold temps. Took it to a dealer and they put some kind of pelets into the radiator??? That didn't do a thing. theres no fix for it that I know of or could find

I'll mess with the intake and give that a try this weekend.

Duke

I get a squeal, too. When it dips into single digit temps, when I start the truck, there is a squeal. However, mine is NOT a whine or whistle. It's more of a grinding, fly-wheel noise. It only lasts for about 5-10 seconds and it's gone. Only at start up after sitting for a while.

I just posted an update to https://www.f150online.com/forums/sh...d.php?t=178962

Well, I got the squeal last night. It is a very loud high pitched squeal that lasted for about 20 seconds. Once the truck startedw warming up, it disappeared. The temp yesterday never broke above -15 degrees outside. The temp with the wind chill was approaching -40 degrees. DAMN!!! THAT'S COLD!!!

Mine did it this morning as well, squealed EXTREMELY loud for quite awhile. It was not belt related, like someone else posted it was more of a metal sound. I turned the heater off immediately as soon as it started doing it, but it continued making the noise for a couple more minutes with the hvac controls off. The truck was not moved the entire time it did it. I just started it, and then it started making the noise... I about shut it off, because the noise was so loud I figured the neighbors were about to come out... The truck is a bone stock 06' F-150 4x4, with the 5.4. The truck only has 160 total miles on it...

BUMP

Anybody figure this cold air whistle out yet? Mine is doing it again, it has a new belt so I know its not that.

It has to do with the intake or engine. I'm running an AF1 and Troyer performance tuning on 92 octane gas (instead of the 87 octane I used to run) and I don't have the high pitched whistle anymore.

Duke

I've had a constant high pitched whine for the past year or more. It just started one day and has never stopped since. No mods or anything of the sort at all. Typical oil filters from Motorcraft or Fram and air filter from K&N. Every single time I am giving it gas it makes the noise and doesn't stop until I take my foot off the gas pedal. What it is I've no idea. It the most annoying thing in the world and I cannot wait to get rid of this truck when the '09's come out. It's not like a little annoying rattle or noise here n there (I have those too), this is just horrible. Paying 42k for a truck that does this just isn't right. Time can't go by fast enough for me, I need a new 150 big time, one that doesn't drive me crazy insane with engine whine. :eek:

try a higher octane and see if that helps. For some odd reason I put on the AF1 and am running custom tuning on 92 octane and the high pitched sound you're talking about when you have your foot on the gas is gone.

I agree though it is a joke. Needless to say my dealer was less then helpful last year. I believe wait till it's warmer was their response. Great I bought a warm weather vehicle only for $42k.:devil:

Duke

mine is just a cold weather whistle, only below say 20 degree's outside. Other than that, truck is great. Somebody has a fix, just need to here from them. I will try higher octane gas.

dude my 04 makes that whistle/whine noise all the time. It does it at 50-60mph, and as soon as you take your foot off the gas it stops. dealer said its a common sound for this truck which i think is b.s, just turn the music up louder