If your vehicle is showing grinding or clunking noise coming from the top of the engine near the supercharger, here are the most likely causes and the parts you'll need to fix each one.
The plastic or spring-loaded coupler that connects the supercharger drive snout to the internal rotors frequently wears out over time. This creates a distinct rattling or clunking noise that sounds like 'marbles in a can', especially at idle or right when the engine is shut off.
The bearings inside the supercharger belt tensioner or nearby idler pulleys frequently fail and emit a grinding or rattling noise. Because these pulleys are mounted right next to the supercharger, the sound is easily misdiagnosed as an internal supercharger failure.
If an aftermarket supercharger pulley was recently installed to increase boost, it may not have been pressed on fully or torqued correctly. A loose pulley will wobble and clunk against the supercharger snout, risking severe shaft damage.
The bearings supporting the supercharger drive shaft can wear out due to high mileage, excessive belt tension, or low supercharger oil. This results in a continuous grinding or growling noise that increases in pitch with engine RPM.
A catastrophic failure of the internal needle bearings can cause the supercharger rotors to crash into each other or scrape against the housing. This produces a severe, loud grinding and clunking noise and requires a complete rebuild or replacement.