whistling

I have been the owner of a 2002 Explorer Sport Trac 4wd for several years now. I am looking for help identifying a noise that the vehicle has made ever since I bought it. While running there is a constant high pitch whistling noise. The best I can describe it is like a dog whistle but within the...

I have a 1996 Explorer with the 4.0L V6 and 214,000 miles on the odometer. (completely stock air intake, engine, and exhaust) I've had it since around 130,000 miles or so and since the day I purchased my Ex, its had this subtle but quite audible high pitched whistle that occurs without fail as...