Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual — part 183

COOLING

CO(w/o STI)

Page

1.

General Description . . . . . . . . . . . . . . . . . . . . ...2

2.

Radiator Fan System . . . . . . . . . . . . . . . . . . . . .7

3.

Engine Coolant . . . . . . . . . . . . . . . . . . . . . . .13

4.

Water Pump . . . . . . . . . . . . . . . . . . . . . . . .15

5.

Thermostat . . . . . . . . . . . . . . . . . . . . . . . ...17

6.

Radiator . . . . . . . . . . . . . . . . . . . . . . . . . 19

7.

Radiator Cap . . . . . . . . . . . . . . . . . . . . . . . 22

8.

Radiator Main Fan and Fan Motor . . . . . . . . . . . . . . ...23

9.

Radiator Sub Fan and Fan Motor . . . . . . . . . . . . . . . .25

10.

Reservoir Tank . . . . . . . . . . . . . . . . . . . . . . .27

11.

Coolant Filler Tank . . . . . . . . . . . . . . . . . . . . ...28

12.

Engine Cooling System Trouble in General . . . . . . . . . . . .29

CO(w/o STI)-2

General Description

COOLING

1. General Description

A: SPECIFICATION

Cooling system

Electric fan + Forced engine coolant

circulation system

Total engine coolant capacity

L (US qt, Imp qt)

Approx. 7.4 (7.8, 6.5)

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 dimen-
sions

Width × Height × Thickness

mm (in)

687.4 × 340 × 16

(27.06 × 13.39 × 0.63)

Pressure
range in
which cap
valve is open

Coolant
filler tank
side

kPa (kg/cm

2

, 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/cm

2

, 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

—

CO(w/o STI)-3

General Description

COOLING

B: COMPONENT

1. WATER PUMP

(1)

Water pump ASSY

(6)

Thermostat cover

Tightening torque: N·m (kgf-m, ft-lb)

(2)

Gasket

(7)

Coolant filler by-pass hose

T1: First 12 (1.2, 8.9)

(3)

Heater by-pass hose

(8)

Clip

Second 12 (1.2, 8.9)

(4)

Thermostat

(9)

Water pump sealing

T2: 12 (1.2, 8.9)

(5)

Gasket

CO-02779

(6)

(4)

(1)

(5)

(2)

T2

(3)

(7)

(8)

(8)

(9)

T1

CO(w/o STI)-4

General Description

COOLING

2. RADIATOR & RADIATOR FAN

(1)

Radiator lower cushion

(12) Radiator main fan shroud

(23) Over flow hose B

(2)

Radiator

(13) Radiator sub fan

(24) Main fan motor

(3)

Radiator upper cushion

(14) Radiator main fan

(25) Sub fan motor

(4)

Radiator upper bracket

(15) Radiator outlet hose

(26) Clip

(5)

Clip

(16) Radiator drain plug

(6)

Radiator inlet hose

(17) O-ring

Tightening torque: N·m (kgf-m, ft-lb)

(7)

Engine coolant reservoir tank cap

(18) Coolant filler tank

T1: 3.4 (0.3, 2.5)

(8)

Over flow hose A

(19) Radiator cap (coolant filler tank

cap)

T2: 4.41 (0.45, 3.25)

(9)

Engine coolant reservoir tank

(20) Engine coolant hose A

T3: 7.5 (0.8, 5.5)

(10) Over flow pipe

(21) Engine coolant hose B

T4: 12 (1.2, 8.9)

(11) Radiator sub fan shroud

(22) Radiator lower bracket

(21)

(20)

(26)

(26)

(19)

(18)

CO-03314

(14)

T1

T3

T3

(9)

(7)

(10)

(8)

(23)

(25)

(24)

(12)

(11)

T2

T2

(5)

(6)

(5)

T3

(1)

(22)

(15)

(5)

(5)

(13)

T1

(2)

(16)

(17)

(3)

(4)

T4