Impreza 2.5 RS Sedan AWD F4-2.5L SOHC (2002)
Water Pump: Testing and Inspection
INSPECTION
1. Check the water pump bearing for smooth rotation.
2. Check the water pump pulley for abnormalities.
3. Using a dial gauge, measure impeller runout in thrust direction while rotating the pulley.
"Thrust" runout limit: 0.5 mm (0.020 inch)
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 inch)
Limit: 1.0 mm (0.039 inch)
5. After water pump installation, check pulley shaft for engine coolant leaks. If leaks are noted, replace the water pump assembly.