Whirring Noise
 

Basically I'm getting this whirring noise from the engine. It sounds like it was coming from the alternator area, so I pulled the drive belt off and the noise stopped.

So basically I think it's either the alternator or the AC compressor. I re-adjusted the belt, so I know it's not that. I'm leaning towards the alternator right now. I just hate to buy a new alternator to find out it was the AC compressor.

Any ideas how to diagnose this more accurately?

take the alternator to a shop. they'll test it for free most likely.

It's more than likely the alternator. If the a/c compressor is off, it only spins the pulley and not the compressor. If it still happens then, that's a pretty good indication it's that alt. If you take the alternator off, of course you could spin it with an electric motor to hear it. More than likely it's bad bearings in the alternator. If it were mine, I would just replace the bearings in the alternator...if the alt is what it turned out to be.

I'm leaning towards the alternator bearings right now. I just have to decide if I'm going to

-change it myself
-have a shop rebuild
-get a new rebuilt one

Any suggestions?

The shop rebuilding is the most expensive, so I wouldn't do that one unless there is a real reason why. I would lean toward buying another one and changing it. First thing is to make sure that is what it really is. Schumi mentioned his a/c made that noise. Turn off the a/c and see if you still have the noise or take the alternator off and spin it. Then buy another one and replace it or have someone else replace it.

The AC is off and the noise is still present. I think I'm going to pull off the alternator and go from there.

I thought a shop rebuild would be cheaper. The new rebuilt ones are going for $ 170. From what I understand all I would need is a $ 5 bearing to be replaced. The alternator is still charging fine.

I guess you can always check on the shop rebuild and you are probably right...all you probably need is the bearing....but the labor is going to make that 5 dollar bearing pretty expensive...I think...but hey, check and see.