There are several reasons a pump can be noisy and each poses a different repair aspect. When air is introduced into a pump it is called cavitation. Sometimes air is introduced because of a poor hydraulic design in the plumbing. Most of the time, air is introduced due to a leak in the pipes that lead into the suction side of the pump. All pumps have two ‘ball bearing’ assemblies, one at the front of the motor and one at the back. The most common bearing failure is due to a leaking seal which allows water to enter the motor through the front bearing. Bearing failures usually start as a ‘whine’ and quickly develop into a loud grinding noise, or an all out ‘screaming’ sound. As a motor repair or replacement is fairly technical, we recommend you call us for a service appointment to determine and fix the source of the noise.