The noise you hear is the fan spinning fast than you heard before. The clutch is sensitive to temp. The hotter the under hood temp is, the faster it spins the fan. Once things cool down, the noise will go away because the fan slows down.
NOTE: It isn't odd to hear it on first start up and then have it quiet down after about 1/4 mile.
Let me know if you have other questions.
Tuesday, June 8th, 2010 AT 10:20 AM