Does this rumbling noise sound like the idler pulleys?

[JFP in PA]

Originally Posted by BoxsterInTheSun

I'm leaning towards replacing just the pulley and hoping that solves the noise issue. Are there other parts of the alternator that might be making the noise, or is it likely that replacing the pulley will solve it?

If the car is a manual transmission, the alternator will have an OAP (overrunning alternator pulley has a one-way clutch allowing the alternator to coast freely), if it is a Tip trans, it will have a simple fixed pulley. The OAP can develop noise, the simple pulley will not. There are also bearings internal to the alternator which can go bad as well.