Grinding Sound from Belt Driven Accessory

[Sam Stevenson]

Okay, I have really been struggling with this one.

 

2001 Porsche Boxster Base 106k Miles

 

At idle, there is a grinding sound that goes on and off every second pretty consistently.  I tried using a screwdriver to hear where this noise is coming from and I feel like it is coming from the alternator, but all of the pulleys seem fine.  the alternator rotates just fine and there is no play in any of the pulleys at all.  I even replaced all of the idler pulleys because they felt a little dry and had some minor bearing noise.

 

I have just taken the alternator out to inspect it further, but I really cannot fault it.  It definitely looks older, but the voltage regulator works just fine and there is no obvious play and it spins freely as far as I can tell.  I have a new pulley to put on it, but have been struggling to get the old one off.  Meanwhile, I can't shake the feeling that I am headed in the wrong direction.  I was thinking about dropping off the alternator at a shop to have them put new bearings in and inspect the brushes just as a general tune-up, but I really would like my car to not sound like it is destroying itself at idle.  Has anyone dealt with something similar before? 

 

Should I just put the alternator back in and keep looking for alternative solutions?  The belt is the same one I bought the car with, but it looks flawless.  I was going to replace it after I got all of the belt accessories sorted out.

[JFP in PA]

2 hours ago, Sam Stevenson said:

Okay, I have really been struggling with this one.

 

2001 Porsche Boxster Base 106k Miles

 

At idle, there is a grinding sound that goes on and off every second pretty consistently.  I tried using a screwdriver to hear where this noise is coming from and I feel like it is coming from the alternator, but all of the pulleys seem fine.  the alternator rotates just fine and there is no play in any of the pulleys at all.  I even replaced all of the idler pulleys because they felt a little dry and had some minor bearing noise.

 

I have just taken the alternator out to inspect it further, but I really cannot fault it.  It definitely looks older, but the voltage regulator works just fine and there is no obvious play and it spins freely as far as I can tell.  I have a new pulley to put on it, but have been struggling to get the old one off.  Meanwhile, I can't shake the feeling that I am headed in the wrong direction.  I was thinking about dropping off the alternator at a shop to have them put new bearings in and inspect the brushes just as a general tune-up, but I really would like my car to not sound like it is destroying itself at idle.  Has anyone dealt with something similar before? 

 

Should I just put the alternator back in and keep looking for alternative solutions?  The belt is the same one I bought the car with, but it looks flawless.  I was going to replace it after I got all of the belt accessories sorted out.

 

Manual gear box Boxster had a declutching alternator pulley that make a racket when the clutch is on the way out.  Fortunately, the clutch is available separately and is not too expensive.