I have a 02 f250 and i was driving the other day and around 3000 rpm I heard this weird noise and it sounded like a what a blower motor would sound like when it starts to go bad. That high pitched sound, but i turned the a/c off and it still did it. But it doesn't make sense that it is a blower motor. Does anyone have any ideas? I have heard it could be timing chains or the camshaft, someone told me the lobes were pressed on the camshaft and they can just go out at anytime. Is that true too. any info would be great thanks

 

mine does this around 2000rpm when it is cool outside. only for the first few minutes of driving. I'm gonna leave it till something breaks. I suspect maybe an alternator or other accessory?

 

Well i found the problem. The PCV valve came apart and i am assuming when it got up around that rpm range it was allowing too much air to flow through. put a new on it and no problems so we'll go with that