While this is being discussed I also have recently replaced my coupler. Here’s the tale...
Marble rattle started after I replaced water pump and I have no reason to believe they were related.
1. Replaced forward most pulley on supercharger belt drive. No change.
2. Replaced coupler with Amazon generic part. No change
3. Replaced Belt. Sound went away for a few miles and came back fully.
4. Replaced tensioner pulley. No change.
If I release a bit of tension on the tensioner while running the car the sound goes away. Not enough for the snout to quit spinning by any means. I’m losing my mind over this noise and am concerned it’s the rotors or something. Also the removal of supercharger belt stops the noise obviously.
