froggman

I just bought a 2006 F150 SuperCrew with a 5.4L engine and since the weather has turned cold, I've noticed an intermittent high pitched squeel coming from the engine compartment. I've replaced the serpentine belt and the idler pulley plus another belt pulley but none of the above helped. I've also had two separete mechanics look at the problem and both are at a loss as to what could be causing the noise. The guess is maybe its an air leak coming from either the intake or vacuum lines. But nobody is really sure.

The noise seems to really become noticable when the temperature gets below 20 degrees and around 2000 rpms, but sometimes it happens at other times.

Has anyone had this same problem with this truck and/or does anyone know where this extremely annoying sound might be coming from?

Thanks in advance for any and all input.

jamesyarbrough

you should have 3 idlers and one tensioner. i would start with the tensioner

joe04f150

Its the alternator...had the same noise on cold days until just recently when I had to replace my alternator. Replaced it with one from the dealer and noise is gone. I read somewhere a long time ago that some models had an issue when its cold out.

bassmaster96

I know this thread is old but I have a few questions about this problem that y'all have.. I think I have the same thing. When it's cold I have a high squeeling sound and after the engine heats up it goes away. It only happens when you push the gas pedal down and when it starts it gets louder as you hold the pedal. If you push the pedal further to the floor it goes away but comes back shortly. Is this the same problem as you guys had?