I have a 2005 f150 with a 5.4 and when i accelerate it sounds like it has a bad bearing and when i really get on it, it screams. I have changed the idler pulleys and it still does it. I have brought it to the dealer ship like 7 times and they say they don't no what it is. They have changed the tension pulley and clutch fan assembly. Then they told me it was my cold air intake so i changed it to stock and still the noise. Then they told me it was my borla exhaust so i put the stock one back on and still the noise. So then i brought it back and they said they don't no what it is and just to drive it till something happens because it is covered under warranty till 2011. So i seen that people were saying that the alternator was making noise so i bought a new one and put it on and the noise was still there so i returned it. So i don't no if anyone has or had the same problem or if anyone knows what it could be because i think it mike be a rod or piston bearing and i don't want to be driving and the engine ceases up on me so if antone could let me know. Thanks Dave

 

Have you read about the cam phaser noise? Use the Advanced Search and look up Cam phasers.

 

Here is a link for a video that discusses the cam phaser. It's #22

http://www.flatratetech.com/index.php?categoryid=4

 

What kind of noise is it?
Cause my truck makes a loud whistling/ chirping sound when I turn it on and while I'm driving it.
I thought it sounded like some kind of belt and have been trying to figure it out.

 

I've watched the video for the noises and stuff but I don't think they mentioned WHY the phaser starts making noise, does anyone know the what happens to the phaser itself and why?