Also called the Serpentine belt. Just a couple inches aft of the Radiator. Sounds like you have an owners manual. On page # 144 of the 1998 manual is a nice drawing of the Poly-V belt and the components it drives. This page is listed under "Layout of Poly-V Belt drive" in the index. Belt should be pretty taut and no flopping around at all.
Paul
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98 E300