Hello,
I have a problem I was hoping that someone has run into before. My alternator bearings recently started to go out (136,000 miles) so I replaced it. Now that I have the new alternator fitted, there is a groaning noise coming from the new alternator. It does not sound to be bearing related, does not affect performance, and it is not loud. It is however, very irritating. You can only hear it if you are standing in front of the vehicle with it idling. Does anyone know what this could be?
Thank you,
Wilson

 

Well, that is odd... Is it a new part? If it is, you might try getting a replacement. Also, the tension on the belt could be off.

 

Yes it is new. I don't think the belt is adjustable, but it does seem to be pretty tight.

 

If your old alternator bearings were noisy, they may have been masking the "groan" you are now hearing. I would take the belt off and check the individual pulleys by hand before returning the alternator.

Chris.

 

The tensioner is not adjustable like you said, but it could be tweaked or broken. The belt will be very tight, but it is only supposed to be so tight. My alternator does not make any noise at all. In general, alternators are extremely quiet because they produce electricity magnetically. The only thing you would hear from them is a slight humming noise from the fan in the front. I think that the alternator you have received is possibly defective. I would take the belt off of it, and see if it spins freely.