For 1990-2009 cars

Complaint/Condition | Possible Cause(s) | Correction(s)
--- | --- | ---
High Pitch Whine with High Electrical Loads | Magnetic noise from generator | Verify additional electrical loads from accessories (e.g., cell phone, CB radio, radar detector, etc.).
Bearing noise | Disconnect regulator connector if the whine is no longer present; tighten to specification all generator mounting bolts. Reconnect regulator; if whine still exists, replace generator.
Squeal, Click, Chirp, or Squeak Seems To Follow Engine rpm | Serpentine belt | Spray belt dressing on serpentine belt. If noise goes away, replace belt.
Generator bearing noise or rotor rub | Check belt tension and ensure all belted accessories are tight. If noise is still present, replace generator.