I drove mom's truck today and it had what I thought a dry bearing noise comming from the alternater pulley and I pulled off the road and the popped the hood and I also noticed the alt was "clicking" it quit when it warmed up. it has 250K on origonal everything. it the alternater going?Should I replace it? it still charges fine.
Dustin
This is mom's truck and I don't want her walking
it is a 95 mazda B3000 5spd that is "gravel road driven"-we live 2.5 mile down a gravel road and she does 35+mph so is it just dirty?

 

I'd bet it's dry and dirty inside the pulley bearing, but so far it's holding up OK. It sounds like the original alternator (and the rest of the truck) has served you well. However, the nature of it is such that those conditions usually lead to bearing failure sooner or later, so this may be a nice little up-front warning sign.

Also, as long as you are sure about the source of the noise, you might want to replace the alternator based on the fact that a bad pulley bearing could be putting more stress on the drivebelt and hence possibly adversely affecting the operation of other drive accessories (PS, A/C) as well.