Water Pump: Inspection

WARNING: This page is about a different variant/trim than selected.

Check the water pump bearing for smooth rotation.
Check the water pump pulley for abnormalities.
Check the impeller for crack or deformation.
Check the clearance between impeller and pump case.
Clearance between impeller and pump case:

Standard 0.4 - 1.6 mm (0.016 - 0.063 in)

Fig 1: Checking Clearance Between Impeller And Pump Case
Courtesy of SUBARU OF AMERICA, INC.
After water pump installation, check the pulley shaft for engine coolant leaks. If leaks are noted, replace the water pump assembly.