Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual - part 95

CO(STI)-12

Radiator Fan System

COOLING

CHECK HARNESS BETWEEN MAIN FAN
RELAY 2 CONNECTOR AND ECM.
Measure the resistance between the main fan
relay 2 connector and ECM connector.

Connector & terminal

(B135) No. 12 — (F27) No. 22:

Is the resistance less than 1 Ω? Go to step

25.

Repair the open
circuit of the har-
ness between
main fan relay 2
connector and
ECM.

CHECK FUSE.
1) Turn the ignition switch to OFF.
2) Remove the fuse No. 2 and No. 26.
3) Check the condition of fuse.

Is the fuse blown out?

Replace the fuse. Go to step

26.

CHECK FOR POOR CONTACT.
Check for poor contact of ECM connector.

Is there poor contact of ECM
connector?

Repair the poor
contact of ECM
connector.

Repair the power
supply circuit to the
main fuse box.

CHECK OPERATION OF RADIATOR FAN.
If the both fans do not rotate at high speed in the
condition of step 2, check whether the radiator
sub fan is rotating.

Does the radiator sub fan
rotate?

CHECK GROUND CIRCUIT OF MAIN FAN
RELAY 2.
1) Remove main fan relay 2 from the relay
holder.
2) Measure the resistance between main fan
relay 2 connector and chassis ground.

Connector & terminal

(F27) No. 19 — Chassis ground:

Is the resistance less than 1 Ω? Go to step

29.

Repair the open
circuit of harness
between main fan
relay 2 connector
and chassis
ground.

CHECK POWER SUPPLY TO MAIN FAN RE-
LAY 2.
1) Turn the ignition switch to ON.
2) Measure the voltage between main fan relay
2 connector and chassis ground.

Connector & terminal

(F27) No. 20 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Go to step

30.

Repair the power
supply line.

CHECK MAIN FAN RELAY 2.
1) Turn the ignition switch to OFF.
2) Remove the main fan relay 2.
3) Measure the resistance between main fan
relay 2 terminals.

Terminals

No. 18 — No. 19:

Is the resistance 1 MΩ or
more?

Go to step

31.

Replace the main
fan relay 2.

CHECK MAIN FAN RELAY 2.
1) Connect the battery to terminals No. 20 and
No. 22 of the main fan relay 2.
2) Measure the resistance between main fan
relay 2 terminals.

Terminals

No. 18 — No. 19:

Is the resistance less than 1 Ω? Go to step

23.

Replace the main
fan relay 2.

Step

Check

Yes

CO(STI)-13

Engine Coolant

COOLING

3. Engine Coolant

A: INSPECTION

NOTE:

When adding the engine coolant, always use SUB-

ARU Super Coolant.

1) Park the vehicle on a level surface.

2) Check the engine coolant amount, and if the

coolant level is low, check for the coolant leakage,

and then add the engine coolant.

(1) Make sure the engine coolant level in the

reservoir tank is between “FULL” and “LOW”

with the engine in a cold condition.

(2) Open the cap of coolant filler tank, and

check that the engine coolant is filled up to the

filler neck position.

B: REPLACEMENT

1. DRAINING OF ENGINE COOLANT

1) Lift up the vehicle.

2) Remove the under cover. <Ref. to EI-28, RE-

MOVAL, Front Under Cover.>

3) Remove the drain plug to drain engine coolant

into container.
NOTE:

Remove the coolant filler tank cap so that engine

coolant will drain faster.

4) Install the drain plug.
NOTE:

Use new O-rings.

5) Install the under cover. <Ref. to EI-28, INSTAL-

LATION, Front Under Cover.>

2. FILLING OF ENGINE COOLANT

1) Pour cooling system conditioner through the fill-

er neck of coolant filler tank.
Cooling system protective agent:

Refer to “SPECIFICATION” for cooling sys-

tem protective agent. <Ref. to CO(STI)-2,

SPECIFICATION, General Description.>

2) Fill the engine coolant into coolant filler tank up

to the filler neck position.
Recommended engine coolant:

Refer to “SPECIFICATION” for recommended

engine coolant. <Ref. to CO(STI)-2, SPECIFI-

CATION, General Description.>

Engine coolant level:

Refer to “SPECIFICATION” for engine cool-

ant level. <Ref. to CO(STI)-2, SPECIFICA-

TION, General Description.>

Engine coolant concentration:

Refer to “ADJUSTMENT” for the recommend-

ed engine coolant concentration. <Ref. to

CO(STI)-14, ADJUSTMENT, Engine Coolant.>

CAUTION:

Do not confuse the cap of coolant filler tank and

cap of radiator.
NOTE:

• When pouring the engine coolant, the radiator

side cap must not be removed.

• The SUBARU Super Coolant contains anti-

freeze and anti-rust agents, and is especially made

for Subaru engines with an aluminum cylinder

block. Be sure to use SUBARU Super Coolant,

since other coolant may cause corrosion.

3) Fill engine coolant into the reservoir tank up to

“FULL” level.

CO-02501

CO-02764

FULL

LOW

CO(STI)-14

Engine Coolant

COOLING

4) Close the coolant filler tank cap, and start the en-

gine. Race 5 to 6 times at 3,000 rpm or less, then

stop the engine. (Complete this operation within 40

seconds.)

5) Wait for one minute after the engine stops, then

open the coolant filler tank cap. If the engine cool-

ant level drops, add engine coolant into coolant fill-

er tank up to the filler neck position.

6) Perform the procedures 4) and 5) again.

7) Install the coolant filler tank cap and reservoir

tank cap properly.

8) Start the engine and operate the heater at max-

imum hot position and the blower speed setting to

“LO”.

9) Run the engine at 3,000 rpm or less until radiator

fan starts and stops.
NOTE:

Be careful with the engine coolant temperature to

prevent overheating.

10) Stop the engine and wait until the engine cool-

ant temperature lowers to 30°C (86°F) or less.

11) Open the coolant filler tank cap. If the engine

coolant level drops, add engine coolant into the

coolant filler tank up to the filler neck position and

the reservoir tank to “FULL” level.

12) Install the coolant filler tank cap and reservoir

tank cap properly.

13) Set the heater setting to maximum hot position

and the blower speed setting to “LO” and start the

engine. Perform racing at 3,000 rpm or less. If the

flowing sound is heard from the heater core, repeat

the procedures from step 9).

C: ADJUSTMENT

1. PROCEDURE TO ADJUST THE CONCENTRATION OF THE SUBARU SUPER COOLANT

CAUTION:

Use the Subaru Super Coolant with a 50 — 60% concentration in order to obtain maximum anti-freeze

and anti-rust performance.

To adjust the concentration of Subaru Super Coolant according to temperature, select the proper Subaru Su-

per Coolant concentration from the table, and add the amount of diluting water corresponding to the required

concentration to the Subaru Super Coolant (concentrated type).

Engine coolant and diluting water:

Refer to “SPECIFICATION” for the recommended engine coolant and diluting water. <Ref. to

CO(STI)-2, SPECIFICATION, General Description.>

Relationship of Subaru Super Coolant concentration and freezing temperature

Subaru Super Coolant concentration

50%

55%

60%

Freezing temp.

–36°C (–33°F)

–41°C (–42°F)

–50°C (–58°F)

CO(STI)-15

Water Pump

COOLING

4. Water Pump

A: REMOVAL

1) Remove the radiator. <Ref. to CO(STI)-19, RE-

MOVAL, Radiator.>

2) Remove the V-belts. <Ref. to ME(STI)-40, RE-

MOVAL, V-belt.>

3) Remove the crank pulley. <Ref. to ME(STI)-47,

REMOVAL, Crank Pulley.>

4) Remove the timing belt cover. <Ref. to ME(STI)-

49, REMOVAL, Timing Belt Cover.>

5) Remove the timing belt. <Ref. to ME(STI)-50,

REMOVAL, Timing Belt.>

6) Remove the automatic belt tension adjuster (A).

7) Remove the belt idler (B).

8) Remove the belt idler No. 2 (C).

9) Remove the cam sprocket LH. <Ref. to ME(STI)-

59, REMOVAL, Cam Sprocket.>

10) Remove the belt cover No. 2 LH.

11) Remove the tensioner bracket.

12) Disconnect the hose from water pump.

13) Remove the water pump.

B: INSTALLATION

1) Install the water pump onto cylinder block LH.
NOTE:

• Use a new gasket.

• When installing the water pump, tighten the bolts

in two stages in alphabetical sequence as shown in

figure.
Tightening torque:

First:

12 N·m (1.2 kgf-m, 8.9 ft-lb)

Second:

12 N·m (1.2 kgf-m, 8.9 ft-lb)

2) Install the hose to water pump.

3) Install the tensioner bracket.
Tightening torque:

24.5 N·m (2.5 kgf-m, 18.1 ft-lb)

CO-02726

(A)

(B)

(C)

CO-02908

ME-04984

CO-00021

ME-04743

(F)

(C)

(A)

(E)

(D)

(B)

ME-04984

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