Engine Cooling System (h4so) Subaru Impreza WRX GH

SPECIFICATION

GENERAL SPECIFICATION

GENERAL SPECIFICATION

GENERAL SPECIFICATION

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CAUTION

1. Wear appropriate work clothing, including a cap, protective goggles and protective shoes when performing any work.
2. Remove contamination including dirt and corrosion before removal, installation or disassembly.
3. Keep the disassembled parts in order and protect them from dust and dirt.
4. Before removal, installation or disassembly, be sure to clarify the failure. Avoid unnecessary removal, installation, disassembly and replacement.
5. Vehicle components are extremely hot after driving. Be wary of receiving bums from heated parts.
6. Be sure to tighten fasteners including bolts and nuts to the specified torque.
7. Place shop jacks or rigid racks at the specified points.
8. Before disconnecting connectors of sensors or units, be sure to disconnect the ground cable from the battery.

SPECIAL TOOL

SPECIAL TOOL SPECIFICATION ILLUSTRATION TOOL NUMBER DESCRIPTION REMARKS 499977100 CRANK PULLEY WRENCH Used to stop rotation of the crank pulley when loosening or tightening crank pulley bolts. (MT model) 499977400 CRANK PULLEY WRENCH Used to stop rotation of the crank pulley when loosening or tightening crank pulley bolts. (AT model) 18231AA010 CAM SPROCKET WRENCH Used for removing and installing cam sprocket. CAM SPROCKET WRENCH (499207100) can also be used. 1B021XU0 SUBARU SELECT MONITOR III KIT Used for troubleshooting for electrical system

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DETECTING CONDITION

1. Engine coolant temperature is 96°C (205°F) or more.
2. Vehicle speed is 19 km/h (12 MPH) or below.

TROUBLE SYMPTOMS

Radiator main and sub fans do not rotate under the above conditions.

SYMPTOMS REFERENCE

Scheme 22

1. Set the vehicle on a lift.
2. Lift up the vehicle.
3. Remove the under cover.
4. Remove the drain plug to drain engine coolant into container. NOTE: Remove the radiator cap so that engine coolant will drain faster.
5. Install the drain plug.

Scheme 23

1. Pour cooling system conditioner through the filler neck. Cooling system protective agent: Refer to "SPECIFICATION" for the cooling system protective agent. SPECIFICATION, General Description. >
2. Pour engine coolant into the radiator up to the filler neck position. Recommended engine coolant: Refer to SPECIFICATION for the recommended engine coolant. SPECIFICATION, General Description. > Coolant level: Refer to "SPECIFICATION" for the recommended engine coolant. SPECIFICATION, General Description. >
3. Fill engine coolant into the reservoir tank up to "FULL" level.
4. Close the radiator cap and start the engine. 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, open the radiator cap. If the engine coolant level drops, add engine coolant into radiator up to the filler neck position.
6. Perform the procedures 4) and 5) again.
7. Attach the radiator cap and reservoir tank cap properly.
8. Start the engine and operate the heater at maximum hot position and the blower speed setting at "LO".
9. Run the engine at 2,000 rpm or less until radiator fan starts and stops. NOTE: Be careful with the engine coolant temperature gauge to prevent overheating.
10. Stop the engine and wait until the engine coolant temperature drops to 30°C (86°F) or less.
11. Open the radiator cap. If the engine coolant level drops, add engine coolant into radiator up to the filler neck position.
12. Attach the radiator cap correctly.
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 at this time, perform the procedures from 9) again.

RELATIONSHIP OF ENGINE COOLANT CONCENTRATION AND FREEZING TEMPERATURE

The concentration and safe operating temperature of engine coolant is shown in the diagram 1. Measuring the temperature and specific gravity of the coolant will provide this information.

[Example]

If the coolant temperature is 25°C (77°F) and its specific gravity is 1.054, the concentration is 35% (point A), the safe operating temperature is -14°C (7°F) (point B), and the freezing temperature is -20°C (-4°F) (point C).

1. Diagram 1

Scheme 24

PROCEDURE TO ADJUST THE CONCENTRATION OF THE COOLANT

To adjust the concentration of coolant according to temperature, find the proper engine coolant concentration in the diagram 1 and replace the necessary amount of coolant with an undiluted solution of engine coolant (concentration 50%).

The amount of engine coolant that should be replaced can be determined using the diagram 2.

[Example]

Assume that the engine coolant concentration must be increased from 25% to 40%. Find point A, where the 25% line of engine coolant concentration intersects with the 40% curve of the necessary engine coolant concentration, and read the scale on the vertical axis of the graph at height A. The quantity of coolant to be drained is 2.1 l (2.2 US qt, 1.8 lmp qt). Drain 2.1 l (2.2 US qt, 1.8 lmp qt) of coolant from the cooling system and add 2.1 l (2.2 US qt, 1.8 lmp qt) undiluted engine coolant solution.

If a coolant concentration of 50% is needed, drain all the coolant and refill with the undiluted solution only.

1. Diagram 2

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1. Remove the radiator. REMOVAL, Radiator. >
2. Remove the V-belts. REMOVAL , V-belt . >
3. Remove the crank pulley. REMOVAL , Crank Pulley . >
4. Remove the timing belt cover. REMOVAL , Timing Belt Cover . >
5. Remove the timing belt. TIMING BELT , REMOVAL, Timing Belt . >
6. Remove the automatic belt tension adjuster.
7. Remove the camshaft position sensor. REMOVAL , Camshaft Position Sensor . >
8. Remove the cam sprocket LH. REMOVAL , Cam Sprocket . >
9. Remove the belt cover LH No. 2.
10. Remove the tensioner bracket.
11. Disconnect the hose from water pump.
12. Remove the water pump.

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Scheme 30

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: 1st 12 N.m (1.2 kgf-m, 8.9 ft-lb) 2nd 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)
4. Install the belt cover No. 2 LH. Tightening torque: 5 N.m (0.5 kgf-m, 3.7 ft-lb)
5. Install the cam sprocket LH. INSTALLATION , Cam Sprocket . >
6. Install the camshaft position sensor. INSTALLATION , Camshaft Position Sensor . >
7. Install an automatic belt tension adjuster with the tension rod held by a pin. AUTOMATIC BELT TENSION ADJUSTER ASSEMBLY AND BELT IDLER , INSTALLATION, Timing Belt . >
8. Install the timing belt. TIMING BELT , INSTALLATION, Timing Belt . >
9. Install the timing belt cover. INSTALLATION , Timing Belt Cover . >
10. Install the crank pulley. INSTALLATION , Crank Pulley . >
11. Install the V-belts. INSTALLATION , V-belt . >
12. Install the radiator. INSTALLATION, Radiator. >

Scheme 31

1. Check the water pump bearing for smooth rotation.
2. Check the water pump pulley for abnormalities.
3. Make sure the impeller is not deformed or damaged.
4. Inspect the clearance between impeller and pump case. Clearance between impeller and pump case: Standard 0.5 - 1.5 mm (0.020 - 0.060 in)
5. After water pump installation, check pulley shaft for engine coolant leaks or noise. If leaks or noise are noted, replace the water pump assembly.

Scheme 32

1. Set the vehicle on a lift.
2. Lift up the vehicle.
3. Remove the under cover.
4. Drain engine coolant completely. DRAINING OF ENGINE COOLANT, REPLACEMENT, Engine Coolant. >
5. Remove the front exhaust pipe. REMOVAL , Front Exhaust Pipe . >
6. Disconnect the radiator outlet hose from thermostat cover.
7. Remove the thermostat cover, and then remove the gasket and thermostat.

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Scheme 34

1. Install a gasket to thermostat. NOTE: Use a new gasket.
2. Install the thermostat and thermostat cover. NOTE: The thermostat must be installed with the jiggle pin facing upward. Tightening torque: 12 N.m (1.2 kgf-m, 8.9 ft-lb)
3. Connect the radiator outlet hose to thermostat cover.
4. Install the front exhaust pipe. INSTALLATION , Front Exhaust Pipe . >
5. Install the under cover.
6. Lower the vehicle.
7. Fill engine coolant. FILLING OF ENGINE COOLANT, REPLACEMENT, Engine Coolant. >

INSPECTION

Replace the thermostat if the valve does not close completely at an ambient temperature or if the following test shows unsatisfactory results.

1. Inspection method Immerse the thermostat and a thermometer in water. Raise water temperature gradually, and measure the temperature and valve lift when the valve begins to open and when the valve is fully opened. During the test, agitate the water for even temperature distribution. The measured value should meet the specification.

Note. Leave the thermostat in the boiling water for five minutes or more before measuring valve lift. Hold the thermostat with a wire or the like to avoid contacting with container bottom.

Opening start temperature

80 - 84°C (176 - 183°F)

Full open temperature

95°C (203°F)

Valve lift

9.0 mm (0.354 in) or more

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REMOVAL

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1. Set the vehicle on a lift.
2. Disconnect the ground cable from the battery.
3. Lift up the vehicle.
4. Remove the under cover.
5. Remove the heat shield cover from radiator. (AT model)
6. Drain engine coolant completely. DRAINING OF ENGINE COOLANT, REPLACEMENT, Engine Coolant. >
7. Disconnect the connectors of radiator main fan motor connector (A) and sub fan motor connector (B).
8. Disconnect the radiator outlet hose from thermostat cover.
9. Disconnect the ATF cooler hoses from ATF pipes. (AT model) Plug the ATF pipe to prevent ATF from leaking.
10. Lower the vehicle.
11. Disconnect the over flow hose.
12. Remove the reservoir tank. REMOVAL, Reservoir Tank. >
13. Remove the air intake duct. REMOVAL , Air Intake Duct . >
14. Disconnect the radiator inlet hoses from the engine.
15. Remove the radiator upper brackets.
16. Lift the radiator up and away from vehicle.

Scheme 43

1. Attach the radiator lower cushion to the hole on the radiator lower bracket.
2. Install the radiator to vehicle. NOTE: Make pins on the lower side of radiator be fitted into the radiator lower cushions on body side.
3. Install the radiator upper brackets and tighten the bolts. Tightening torque: 12 N.m (1.2 kgf-m, 8.9 ft-lb)
4. Connect the radiator inlet hose.
5. Install the air intake duct. INSTALLATION , Air Intake Duct . >
6. Install the reservoir tank. INSTALLATION, Reservoir Tank. >
7. Connect the over flow hose.
8. Lift up the vehicle.
9. Connect the ATF cooler hoses. (AT model)
10. Connect the radiator outlet hose.
11. Connect the connectors of radiator main fan motor connector (A) and sub fan motor connector (B).
12. Install the heat shield cover. (AT model) Tightening torque: 3 N.m (0.3 kgf-m, 2.2 ft-lb)
13. Install the under cover.
14. Lower the vehicle.
15. Connect the battery ground cable to battery.
16. Fill engine coolant. FILLING OF ENGINE COOLANT, REPLACEMENT, Engine Coolant. >
17. Check the ATF level. INSPECTION , Automatic Transmission Fluid . >

Scheme 44

1. Remove the radiator cap, fill the radiator with engine coolant, and then install the tester to the installation position of cap.
2. Apply a pressure of 157 kPa (1.6 kg/cm 2, 23 psi) to the radiator and check the following points

1. Leakage from the radiator or its vicinity
2. Leakage from the hose or its connections

Scheme 45

1. Attach the radiator cap to tester.
2. Increase pressure until the tester gauge pointer stops. Radiator cap is functioning properly if it holds the service limit pressure for five to six seconds. Replace the cap if it is opened under a pressure less than the service limit value. Standard: 93 - 123 kPa (0.95 - 1.25 kg/cm 2 , 14 - 18 psi) Service limit: 83 kPa (0.85 kg/cm 2 , 12 psi)

Scheme 46

1. Set the vehicle on a lift.
2. Disconnect the ground cable from the battery.
3. Lift up the vehicle.
4. Remove the under cover.
5. Disconnect the connector (A) of the main fan motor.
6. Remove the heat shield cover. (AT model)
7. Remove the ATF hose from the clip of the radiator main fan motor assembly. (AT model)
8. Lower the vehicle.
9. Disconnect the over flow hose.
10. Remove the reservoir tank. REMOVAL, Reservoir Tank. >
11. Remove the bolts which hold the radiator main fan shroud to the radiator.
12. Remove the radiator main fan motor assembly.

INSTALLATION

Install in the reverse order of removal.

Note. If the installation of the radiator main fan motor assembly is difficult, attempt installation after loosening the bolts which hold the radiator sub fan motor assembly.

Tightening torque

7.5 N.m (0.76 kgf-m, 5.5 ft-lb)

Tightening torque

3 N.m (0.3 kgf-m, 2.2 ft-lb)

Scheme 47

1. Remove the clip which holds motor connector onto the shroud.
2. Remove the nuts which hold the fan to the fan motor.
3. Remove the bolts which hold fan motor onto shroud.

Scheme 48

ASSEMBLY

Assemble in the reverse order of disassembly.

Tightening torque

5 N.m (0.5 kgf-m, 3.7 ft-lb)

Tightening torque

3.4 N.m (0.35 kgf-m, 2.5 ft-lb)

Scheme 49

1. Set the vehicle on a lift.
2. Disconnect the ground cable from the battery.
3. Lift up the vehicle.
4. Remove the under cover.
5. Remove the connector (B) of sub fan motor.
6. Remove the heat shield cover. (AT model)
7. Remove the ATF hose from the clip of the radiator sub fan motor assembly. (AT model)
8. Lower the vehicle.
9. Remove the air intake duct. REMOVAL , Air Intake Duct . >
10. Remove the bolts which hold the radiator sub fan shroud to the radiator.
11. Remove the radiator sub fan motor assembly from underneath the vehicle.

Install in the reverse order of removal.

Tightening torque

7.5 N.m (0.76 kgf-m, 5.5 ft-lb)

Tightening torque

3 N.m (0.3 kgf-m, 2.2 ft-lb)

Scheme 50

1. Remove the clip which holds the fan motor connector to the shroud.
2. Remove the nuts which hold the fan to the fan motor.
3. Remove the bolts which hold fan motor onto shroud.

Assemble in the reverse order of disassembly.

Tightening torque

5 N.m (0.5 kgf-m, 3.7 ft-lb)

Tightening torque

3.4 N.m (0.35 kgf-m, 2.5 ft-lb)

1. Disconnect the over flow hose connected to the radiator filler neck.
2. Push in the hook (A), and pull the reserve tank in the direction of the arrow to remove.

Scheme 51

Install in the reverse order of removal.

Make sure the engine coolant level is between "FULL" and "LOW".

POSSIBLE CAUSE