AO Smith pool pump runs but is very loud, with a high-pitched whine or grinding noise from the motor end.

Safety First: Turn OFF power and lock out the breaker before working on the pump.

• Confirm noise source: Use a mechanic’s stethoscope or a long screwdriver to listen at the motor body versus the wet end. Bearing noise will be loudest at the motor.
• Check for shaft play: With power OFF, grasp the motor shaft or fan and wiggle side-to-side. Excessive play indicates bearing failure.
• Inspect for leaks: Look for water trails or rust at the motor face where it meets the pump seal plate. A leaking shaft seal often leads to bearing failure.
• Replace bearings or motor: For many AO Smith pool motors, bearings can be replaced by a motor shop. For homeowners, replacing the entire motor assembly with an equivalent AO Smith model is often more practical.
• Replace shaft seal: Always replace the mechanical shaft seal in the pump wet end when installing a new or rebuilt motor to prevent repeat failure.