I have a 2000 Mercury Mountaineer 5.0L V8. Recently it has developed a squeak in one of the pulley wheels. I think it is the middle one but it may be the alternator. My question is can I change these pulleys or do I even need to? My mechanic said its nothing to worry about but I am of the opinion that bad news does not get better with age. A squeak indicates that something is not right. Thanks BH
Your mechanic doesn’t own the car so if you want to deal with it then why not do so? I would. Mechanics advise. Customers decide. The only thing you want to be sure to do is figure out exactly where the noise is coming from so that you don’t end up on a wild parts changing expedition.
After ~11 years of use, it is very possible that the bearings in one of the pulleys are dry.
If you wait until the bearings in the pulley seize, that can result in destroying the serpentine belt.
If the serpentine belt snaps while you are driving, you will lose the power assist for your steering, and the alternator will stop turning–very possibly causing your battery to go dead. Ergo–waiting until the bearings in the pulley seize will be very inconvenient at the least, and possibly a safety hazard.
This may be your signal to seek out a new mechanic.
I believe that the water pump on this engine is run by the serpentine belt as well (though I could be mistaken), in which case you also lose cooling if the serpentine belt fails. That could also lead to an overheating engine - in other words, you WILL end up on the side of the road - you won’t be able to limp in to a shop.
If the problematic pulley is the idler (would not be surprising - I’ve known more people to have idler pulleys fail than any other pulley), the swap should be relatively straightforward - and the part should cost under $20.