After every 100k miles make sure you replace the tensioner and idler pulleys along with the serpentine belt if needed. Also, it is not unusual to see the fan clutch worn out by this time. I have had three towed in off the interstate over the past 6 months that lost the idler pulley. They were all between 110k miles and 140k miles. This is good preventive maintenace in my opinion.

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Jim