I think the alternator is maybe going bad in my WJ? I've helped replace alternators on other vehicles, but never actually have had one begin to fail on me yet.

Right now my WJ engine compartment at the passenger front side is way louder than it used to be. It is not obnoxious. If you did not know the Jeep, or Jeeps, maybe you might not even notice it? It is louder though for sure. I definitely feel as though I have it isolated to be coming from the alternator, but I am not definitively 100% certain? I would say I am 99% sure though.

It whines. Not like a bearing squeel/whine. The noise increases with the application of throttle to match the engine RPMs too. I notice the volts meter in the dash says about 14V or just barely below this while it is at idle. This gauge immediately shows going up to over past 14V with 2000 RPMs being sustained by throttle inputs.

I read that an alternator may develop a whine type of noise when it starts to provide too much current, as it is going bad, sometimes before it is about to fail?

I guess I know what to do. Repair the noise.. Rebuild the Mopar alternator? Or, replace it with something else? What do you normally do with these?

 

Sometimes a bearing will fail while the alternator is still producing all the juice you need. So, I suggest two things:

1. A voltmeter. No, not your dash gauge. A real digital voltmeter. If your alternator is good, you should see around 13.8 volts at the battery while the engine is idling.
2. A mechanic's stethoscope. You want to listen to the alternator bearing. Just find a spot on the case near the bearing and touch the 'scope to it. You will be amazed at what you can hear.

 

I've got a Littman Master Cardiology II stethoscope. But, it is supposed to be for use on humans. I bet it could be improvised for use? I am thinking I need a new alternator.

(edited to add):
I am needing to go to the auto parts store tomorrow. I will have them check the battery out for me, its voltage while I am there. I broke my DVOM.

 

The mech steth is a great tool for a lot of things. Even the Harbor Freight cheapo works. I saw them today at AutoZone for about 12 bucks. Looked pretty good. Put that end on anything that has a rotating part (idler pulley, water pump, alternator, etc.) and you'll almost instantly know if the bearing is bad.

If it is, yes, you need a new alternator.