My 97 Explorer makes a medium to high pitch whine only while idling. There seems to be no effect to performance. It has been doing this for a couple years. The truck has 96,000 miles on it and has been flawless since we bought it used with 29,000 miles 3 years ago. This is my second Explorer and have got to give them high marks.
Also, what kind of mileage is to be expected from the brake pads? I have not had the pads changed on this truck but am planning on having them looked at this week. I'm sure they must be due by now?