hi, i have had my 2001 Wrangler (manual, 5-speed) since I bought it new. In the last 2 years, it has developed a very loud and steady piercing whistle when the engine is running, either at an idle or on the road. my mechanic tried replacing the water pump, serpentine belt and radiator -- but that did not help. he knows a jeep rep and the rep looked at it too. no one can figure out what it is, but it's very loud and high pitched and driving me crazy. any ideas? the Mechanic said that, since it is also happening at a standstill, it can't be wind whistling through a hole in the body. thanks very much!