If your pool pump motor start to get noisy, it often means that your motor's bearing are failing and need to be replaced. If a failing bearing is not replaced promptly, the motor can overheat and cause the windings to fail. This guide discusses possible causes of a noisy motor including bad bearings.
BE SAFE - Before you even touch the motor, MAKE SURE THE POWER IS OFF. Always turn the power off at the electric service fuse or breaker box. To prevent electrical shock, use a meter to check for electrical shorts and be sure the motor is securely grounded and bonded in conformity with local codes. Do not work on electrical devices if water or moist conditions are present and cannot be avoided.
CHECK LOOSE INTERNAL PARTS - Turn the motor shaft. If it is rough or tight, check inside for a loose or broken impeller or diffuser. They wear and start to wobble or sometime a hard object like a small stone or not will get inside and crack part of the impeller. Note: This picture is cut-away to be able to show the inside components of a pump.
CHECK BEARINGS - If a tight shaft is not due to loose internal parts, check the motor's bearings. They may be starting to fail and will need to be replaced. Also be aware that bearing noise is often a sign that the pump seal has been leaking. Always change the pump seal when you change the bearings. Also always change both bearing if one is bad. The other is sure to follow.
CHECK PUMP CAVITATION - If you see a lot of air in your pump's strainer basket, your pump is cavatating and this will generate noise. Cavitation is generally caused by an air leak in the suction side of the pump or by shutting down most of your intake valves so that you do not provide sufficient water to the pump.