Subaru LEGACY 2004 Service Manual page 210

Water Pump
COOLING
Clearance between impeller and pump case:
Standard value
0.5 — 1.5 mm (0.020 — 0.060 in)
CO-00293
5) After water pump installation, check the pulley
shaft for engine coolant leaks and noise. If leaks or
noise are noted, replace the water pump assembly.
CO(H4SO 2.0)-17