Idler runaway

[powerhoghp]

1997 Explorer Sport 4.0L OHV, the one without the death chain option
Anyways, pulling or rather nailing onto I-81 after a trip to Lowe's, smoke billowed into and filled the cabin. Loud rattle followed by clunk, which was later known to be the idler pulley shooting off down the road taking the serpentine belt with it . Rode a few mile down the road and pulled into a hospital parking lot. Belched up coolant just as I got to a stop. Called friend and had him bring me a belt, not yet noticing the missing pulley Tried to put the belt on but it seemed to big, checked the label, it was correct, checked the diagram again and noticed no idler. I guess that what that mysterious squeal the went away at operating temp was... Got home and looked on the explorer forum and found that this was surprisingly common. Although if this is the only real problem I've had in 140000 miles, I'm fine with that.