Serpentine belt slides off of the fan.
My truck started to overheat yesterday and so I thought it was a problem until I opened the hood. Noticing the belt has slid off the fan I reassembled the belt and turned on the truck to make sure everything was in order. The belt then slid off 1/4 of the fan. Is there something that would cause this?
How old is belt? Check all idler and tensioner pulleys. Check all acc for loose pulleys and loose mounting bolts .(ac, alter, water pump, fan, ect).
Those are obvious. The tensioner and idle pulleys do fail. If the belt comes off, the most likely culprit is the water pump. See if the fan moves up and down or side to side. It only takes a little movement for the belt to come off at the fan. My fan pulley is smooth. I have seen some with ridges on the outside edges that will help it stay on. In just discovered that the water pump shaft is loose although it is not leaking coolant yet.