This has only happened a few times and it goes awa y after a while. My alternator makes a "rattling" sound. It sounds similar to baseball cards in bicycle spokes. When it happens it only does it at idle or when I am slowing down to stop or for traffic etc., I have cheked to make sure nothing is in the fan or loose and evrytime I have checked it is coming from the alternator. Does anyone have any answers as to why/ what could be causing this??


Tahnks Drew

 

The alternator might have snapped a band, what is you're voltage reading?

Also, just curious.... check to see if you're harmonic balancer is rubbing up against you're timing chain cover.

 

I had one that used to do that.... it would do it when I shut the engine off, in fact it woudl keep doing it for a second or 2 after the alt stopped..... very perplexing.

Turned out, there's a ring of steel wrapped around the windings of the armature, that's kind of swaged in place. Mine had worked loose and was free to spin around the armature. It made a weird scraping, rattling kind of noise. It didn't affect the working of the alt, all it did was drive the owner nuts, until I finally broke down and took it apart to see where that noise was coming from.