I'd see if the belt is rubbing on the cover.
But I'll tell you my story. I heard a Tapping/Klacking sound coming from my timing cover. Pin pointed it to the bottom of the cover. Never thought anything of it. Then I blew a head gasket so I had to pull all that BS off. Found a 1/2" bushing wedged/melted into the lower timing cover and when the belt hit it to wedge it in the cover it caused a "V" shaped gash in the center of the belt. Never heard the Tapping/Klacking after the new belt and taking out the bushing.
