I have never heard of a fan clutch failing the way you described. They usually die a slow death and fail to come on when they should. Are you saying your gauge readings are not higher than normal when it engages? What temp does it come on now vs before? Do you see any leakage from it? It comes on when the air gets to a certain temperature. They vary a little based on the year. As Paul said your dash gauge could also be off. Mine was off 20 degrees higher than my thermostat housing and I thought it wasn't coming on soon enought I shot it with an IR gun. If you already have it out I would use a heat gun and an IR gun and spin the fan and see what temperature it engages at. If it engages around 160+ or - 10 degrees your fan is working right.
