I have a 2000 Grande Caravan 6 cylinder 3.5 liter engine. After a cold start there is a loud crunching metal sounds lasting about 1 minute. It then stops and does not happen again when the engine warms up. All fluid levels are topped up and there is no fluid leakage. The noise appears to come from the alternator or the serpentine belt but it's difficult to be sure exactly. Any ideas what may cause this annoying sound?

 

I suggest that you remove the serpentine belt with the engine cold and turn each of the components by hand. This should allow you to feel what component is causing the noise.