docsouce wrote:
Well I did the old "2 foot length of heaterhose trick" (put one end near your ear and the other near the suspected noise culprit" acts like a stethoscope ya know) and it sounded like the idler was chirping. Now that you mentioned it I think I'll change out the belt and see what happens. I don't have an extra one and I should carry one especially when most of our trips end up in the middle of nowhere (by choice).
Not a "reliable" way of finding this type of noise.
There are a lot of internal moving parts just under those idlers, V8 and V10 Triton motors share similar design with the overhead cam system. You have cam chain tensioners and guides right under the idlers and any noise made there can easily be transferred to the outside..
Remove the belt and give the idler a spin by hand, should be smooth and make no noise. Smooth and no noise and most likely the pulley bearings are good (bearings are sealed and moisture shouldn't be able to damage them). While the belt is off spin the alternator, PS pump and A/C pulleys and verify they run smooth.
As someone else noted, alignment off the pulleys can also affect the belt which could cause chirping, however, if it hasn't done this from day one I can't see how the idlers may have come out of alignment.
In your case I suspect that the belt just might be the culprit from the shear amount time that MHs tend to sit around and not being driven.
Fair chance that there is nothing wrong with idlers OR belt and the chirping is from lack of use and pretty much just an annoyance. If that is the case, changing the belt is the easiest and lowest cost to find out.