[Fido Racing]

Hi all - I have a 2005 F150 2wd, 4.6 with Automatic. Ever since the temps dropped, I have a really high pitched whine/whistle coming from the engine compartment, but only at very specific RPM. First spot is around 1700, then again around 2000 to 2100 rpm. Trouble is, thats right where you typically drive.

I have done some searching, and every where I look it seems to say that its the idler pulleys or tensioner for the serpentine belt. Replaced all the idler wheels, the tensioner, and the belt itself, and it still does it. I also checked for vacuum leaks, and cleaned out the throttle body.

I've ruled out the transmission, because it does it parked in the driveway as well as on the road. No leaks, everything is full of fluid, and it makes no difference if the defroster is on or off. Its very RPM dependent, but only under 35 degrees.

Any ideas? This has been driving me nuts, and its to the point where I'm ready to get rid of the truck because of it. Thanks for any help you have!

 

[Mr Mac]

Have you tried to listen (using a stethoscope) to the individual accessories (i.e. PS pump, alternator, etc.) to see if it's a bearing issue?

 

[Detroit84]

Just dealt with a similar issue. Mine made the whining noise between 55 and 65 mph though.

First thing I did was replace the idler pulley, which did need to be replaced, but still heard the noise...

Just ended up being a loose cable that was rubbing when at those speeds... Weird I know, but just securing the cable fixed the issue.


Really cheap fix!