98 1500 w/t questions

The alternator bearings are a common cause of this engine compartment noise. As to the wiper noise, does it only happen when the wipers are on?

My wife's Chevy minivan had an intermittent squeal. I ignore it but then the low cooklant level light came on. There was never any sign of a leak. After they replaced the water pump they found out it was.a coolant leak at the manifold : the leak wasn't visible because the heat of the engine kept drying it up.

Can the bearings be replaced or would I need a new alternator, assuming the noise dosent go away after I replace the serpentine belt? The wiper noise is only when they are on. If I tilt the wiper arms back and turn them on, the noise is definitley less noticeable, but when you place them back on the windshield, it gets louder. Both of these noises go away for short periods and then return. Thanks!

Toad

If it is the alt making the noise, replace it, but again thats IF its the source. The source could also be the idller pulley, ot the pulley on the belt tensioner, which are both more common causes.

Whitelightning.

Is there a good method of figuring out which part is causing the problem? It seems like it is probably a pulley of some sort, do I just have to trial and error it? I have seen the stethoscope/metal probe thingies, are they good for this purpose?

Toad

The stethoscope works well, place the tip on the object you think is making the noise. Or carefully give the bearing area of the suspected pulley a little shot of WB40, or even brake clean.

Whitelightning

Is this truck white? Did you buy it in Florida? I knew a guy that had one. I never could find the noise. It seemed to emit from behind the glove box. Very strange.

At 100,000 miles I'd put my money on either an ALTERNATOR bearing OR TENSIONER PULLEY bearing. Of the two of these, I'd suspect the tensioner pulley brg first. Could also be both !