Subaru Impreza 2003 Service Manual page 340

COOLING
C: INSPECTION
1) Check the water pump bearing for smooth rota-
tion.
2) Check the water pump pulley for abnormalities.
3) Using a dial gauge, measure the impeller runout
in thrust direction while rotating the pulley.
"Thrust" runout limit:
0.5 mm (0.020 in)
4) Check the clearance between impeller and
pump case.
Clearance between impeller and pump case:
Standard
0.5 — 0.7 mm (0.020 — 0.028 in)
Limit
1.0 mm (0.039 in)
5) After water pump installation, check the pulley
shaft for engine coolant leaks. If leaks are noted,
replace the water pump assembly.
WATER PUMP
CO-00028
CO-00029
CO(H4SO)-18