just started, truck was warmed up, and is in a cycle. Its quiet then gets louder, and louder, and ear piercing loud, then goes away for several, several, 30-60 maybe, seconds, then the cycle starts up again. at any rpm, and idle. Any ideas? 03 SUPERCHARGED HD. 16800 miles and this starts.

 

incredible post. I have been having this issue as well, and have been investigating the reason. From the outset it was all the more a whistle, presently sounds more like metal on metal clatter, sort of like a course. I'm thinking alternator. much obliged.

Regards,
auto parts store

 

Is this the whistle in question? I’ve been hearing it for a while now and it’s progressively getting worse.

 

Engine whistles always comes from three things, 1) Intake, 2) Exhaust, 3) serpentine belt. make sure all these things are clear and nothing is having contact with any thing

 

Hello, I wanted to post this hoping it will help someone. I spent a long time trying to find out what was causing the sound coming from my engine when I reved up my F150 to 2500 RPMs.
I could hear the sound inside of the cab, but barely if any under the hood.
I put headers on the motor ( thinking it was something to do with the exhaust) No luck still there.
I pulled the tranny and replaced the torque converter, (sounded like it was coming from there) No luck, still there.
I replaced idler pully, alternator, water pump, Still no better.
I finally thought maybe my flex plate the torque converter is attached to. It might have a crack and start vibrating at higher RPMs.
I replaced the flex plate with a heavy duty one.(Still no change)
I noticed that the noise (sounding more and more like a metal grinding) was now starting at 2000 RPM.
I left the truck parked for almost 6 months out back.
I found that a squirrel had made a next under the hood.
after cleaning out the nest and finding that the squirrel had eaten some of my vacuum lines,
I replaced the chewed up ones.
Suddenly the noise went away.
This whole time it seems that the noise was a vacuum leak close to the bac of the engine.
I bought a kit for the vacuum lines and replaced everything after that.
The sound never came back.

 

hi gang i need an engine for my 2006f150 xlt 5.4L vin 5 8th digit. everywhere i look the motors have SOHC, but my engine is a DOHC. I can't seem to find one. I need some HELP please.

 

The F150s never came with a DOHC 5.4
The only option on the 5.4 was 2 or 3 valve heads.
So unless someone swapped in some Mustang heads in you probably have SOHC heads.
Having 06 5.4 myself it came with SOHC 3 valve heads

The SOHC or DOHC is only for the each head not the whole motor.

Why do you think you need a new motor?
​​​​​Why are you posting about it in a old *** thread start a new one

 

Listen jamie930
first I am just researching this issue. I have 2 chains off the crank and a cam on each head switch makes it a dohc. I have searched for a motor and SOHC is the only motor that i find fits my truck soooooo I just wanted someone with a little more experience to give me some input on why this engine is a 3 valve dohc motor in my truck. I am in this old *** thread because I don't normally go into these forums. I usually talk in real life to a real human like a man. So if you are not going to help go back in your moms basement and be quiet.

 

If you would have read my reply is instead of flying off the handle. You would realized that you have a SOHC motor.
So read this
1 cam per head= SOHC
2 cam per head = DOHC

There a lot of info here about just about every problem the F150 has ever had.
With your attitude coming from a person with 3 posts I doubt many will help.

By the way many people here have been told they need a new engine, but after doing some research here they fix it themselves.