Since rebuilding my topend a month or so ago i've had a bit of a vacuum leak that i could hear through the airbox as well as a little squeal at idle from something in the beltline. Well, last saturday my wp decided it wanted to start pissing from the weephole so i replaced it with what looked like a recently replaced wp from a junkyard car. Since it failed late in the day on sat and i needed to drive my truck to work on monday a junkyard part was really the only feasible option. No one had one in stock that was open on sunday that didnt want an arm and a leg and a kidney for a new wp.

Replaced the wp and still had a bit of a whine at idle. Last night while sorting the vacuum leak (turned out it was the upper intake plenum joint is where the leak was) I hit the serpentine belt with some belt dressing.. wow, what a mistake. I started the truck this morning and the beltline just howled.. Fortunately i had a spare belt sitting around so i swapped it over and was back to just the squeak at idle.

I've narrowed it down to one of the three accessories as it doesn't whine at idle with the belt removed. Going to get a stethoscope and see which is the culprit tonight. A/C pulley rotates nice and freely, alt is a little stiff as well as the power steering. Hope its one of the latter two as the whole pulling the ac and getting it recharged is a big pita..

 

You should be able to hear the alternator bearings (and others) with a stethoscope or listening stick quite easily.