If the alternator EVER worked with that pulley, then the pulley is NOT the problem. Click these & read the captions:
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I'd also inspect ALL the pulleys, and the serpentine belt, and the tensioner. If the belt is glazed or oily, or if the tensioner is close to its loose limit, a smaller pulley will only make it worse. A smaller pulley also makes the belt bend more, which makes it age faster. And because there's less belt surface area in contact with the pulley, the belt needs more tension to apply the same torque to the pulley, which the tensioner ISN'T built to provide. That also makes the belt more-prone to slip, which causes it to wear away faster. Either way: wash the front of the engine thoroughly with SimpleGreen/PurplePower & a LOT of water, and repair any leaks that could get onto the belt (including oil coolers forward of the fan).
. . . . . I'd also inspect ALL the pulleys, and the serpentine belt, and the tensioner. If the belt is glazed or oily, or if the tensioner is close to its loose limit, a smaller pulley will only make it worse. A smaller pulley also makes the belt bend more, which makes it age faster. And because there's less belt surface area in contact with the pulley, the belt needs more tension to apply the same torque to the pulley, which the tensioner ISN'T built to provide. That also makes the belt more-prone to slip, which causes it to wear away faster. Either way: wash the front of the engine thoroughly with SimpleGreen/PurplePower & a LOT of water, and repair any leaks that could get onto the belt (including oil coolers forward of the fan).
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