All I can tell you is that I had a noise in my 2001 with a 3.8 that drove me crazy over a 20,000 mile period. I changed idler pulley, AC clutch, etc. Finally the alternator locked up. It was the alternator all along. When finally failed and hot the alternator prevented the engine from turning over. When cold and you spun the pulley, you would swear that the bearing was fine. Go figure.......