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Section 12 (Engine Cooling System (WRX-STI)): General Description: Specification

WARNING: This page is about a different car, the 2013 Subaru Impreza. However, it is still accessible from the selected car via links, so may be relevant.
Cooling system Electric fan + Forced engine coolant circulation system
Total engine coolant capacity L (US qt, Imp qt) Approx. 7.7 (8.1, 6.8)
Water pump Type Centrifugal impeller type
Discharge performance Discharge rate L (US gal, Imp gal)/min. 200 (52.8, 44.0)
Pump speed - Discharge pressure 6, 000 rpm - 225.4 kPa (23.0 mAq)
Engine coolant temperature 80°C (176°F)
Impeller diameter mm (in) 76 (2.99)
Number of impeller vanes 8
Pump pulley diameter mm (in) 60 (2.36)
Clearance between impeller and pump case mm (in) Standard 0.5 - 1.5 (0.020 - 0.059)
Thermostat Type Wax pellet type
Starting temperature to open 76 - 80°C (169 - 176°F)
Fully opens 91°C (196°F)
Valve lift mm (in) 9.0 (0.354) or more
Valve bore mm (in) 35 (1.38)
Radiator fan Motor input Main fan W 120
Sub fan W 120
Fan diameter / Blade Main fan 318.5 mm (12.54 in)/9
Sub fan 318.5 mm (12.54 in)/11
Radiator Type Down flow
Core dimensions Width x Height x Thickness mm (in) 687.4 x 340 x 16
(27.06 x 13.39 x 0.63)
Pressure range in which cap valve is open Coolant filler tank side kPa (kg/cm2 , psi) Positive pressure side Standard 93 - 123 (0.95 - 1.25, 14 - 18)
Limit 83 (0.85, 12)
Negative pressure side Standard -1.0 - -4.9
(-0.01 - -0.05, -0.1 - -0.7)
Radiator side kPa (kg/cm2 , psi) Positive pressure side only Standard 122 - 152 (1.24 - 1.55, 18 - 22)
Limit 112 (1.14, 16)
Fins Corrugated fin type
Reservoir tank Capacity L (US qt, Imp qt) 0.45 (0.48, 0.40)
  Recommended materials Item number Alternative
Coolant SUBARU SUPER COOLANT (Concentrated type) - -
SUBARU SUPER COOLANT (Diluted type) K0670Y0001
Water for dilution Distilled water - Soft water or tap water
Cooling system protective agent Cooling system conditioner SOA345001 -