Engine Cooling System (H4DOTC) (except Sti) Subaru Impreza WRX STI GR

SPECIFICATION

SPECIFICATION CHART

COOLANT SPECIFICATION

Scheme 70

Tightening torque: N.m (kgf-m, ft-lb)

T1: First 12 (1.2, 8.9)

Second 12 (1.2, 8.9)

T2: 12 (1.2, 8.9)

Scheme 71

Tightening torque: N.m (kgf-m, ft-lb)

T1: 3 (0.3, 2.2)

T2: 3.4 (0.3, 2.5)

T3: 4.41 (0.45, 3.25)

T4: 7.5 (0.8, 5.5)

T5: 12 (1.2, 8.9)

C: 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 burns 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 battery.
9. Prepare a container and cloth to prevent scattering of engine coolant when performing work where engine coolant can be spilled. If the oil spills, wipe it off immediately to prevent from penetrating into floor or flowing out for environmental protection.
10. Follow all government and local regulations concerning disposal of refuse when disposing engine coolant.

SPECIAL TOOL

SPECIAL TOOL DESCRIPTION ILLUSTRATION TOOL NUMBER DESCRIPTION REMARKS 499207400 CAM SPROCKET WRENCH Used for removing and installing exhaust cam sprocket. 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) 499977500 CAM SPROCKET WRENCH Used for removing and installing intake cam sprocket. 1B022XU0 SUBARU SELECT MONITOR III KIT Used for troubleshooting the electrical system

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GENERAL TOOL

GENERAL TOOL DESCRIPTION

Scheme 76

INSPECTION

OPERATING CONDITION

OPERATING CONDITION REFERENCE

DIAGNOSIS

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

DIAGNOSIS PROCEDURE CHART

Scheme 77

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 coolant filler tank cap so that engine coolant will drain faster.
5. Install the drain plug.
6. Install the under cover.

Scheme 78

1. Pour cooling system conditioner through the filler neck. Cooling system protective agent: Refer to "SPECIFICATION" for cooling system protective agent. Ref. to «SPECIFICATION»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/cooling-system-mechanical/#engine-cooling-system-h4dotc-except-sti__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 «SPECIFICATION»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/cooling-system-mechanical/#engine-cooling-system-h4dotc-except-sti__specification) , General Description. Engine coolant level: Refer to "SPECIFICATION" for engine coolant level. Ref. to «SPECIFICATION»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/cooling-system-mechanical/#engine-cooling-system-h4dotc-except-sti__specification) , General Description. Engine coolant concentration: Refer to "ADJUSTMENT" for the recommended engine coolant concentration. Ref. to «ADJUSTMENT»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/cooling-system-mechanical/#engine-cooling-system-h4dotc-except-sti) , 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 antifreeze and anti-rust agents, and is especially made for Subaru engines with an aluminum cylinder block. Always use SUBARU Super Coolant, since other coolant may cause corrosion.
3. Fill engine coolant into the reservoir tank up to "FULL" level.
4. Close the coolant filler tank 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, then 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.
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 maximum hot position and the blower speed setting to "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 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 heater core, repeat the procedures from step 9).

PROCEDURE TO ADJUST THE SUBARU SUPER COOLANT CONCENTRATION

To adjust the concentration of SUBARU Super Coolant according to temperature, find the proper SUBARU Super Coolant concentration in the table, and add dilution water to the SUBARU Super Coolant (concentrated type) until it reaches the proper dilution.

SUPER COOLANT CONCENTRATION REFERENCE

Engine coolant and diluting water

Refer to "SPECIFICATION" for recommended engine coolant and diluting water. Ref. to SPECIFICATION , General Description.

Scheme 79

Scheme 80

Scheme 81

1. Remove the radiator. Ref. to «REMOVAL»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/cooling-system-mechanical/#engine-cooling-system-h4dotc-except-sti) , Radiator.
2. Remove the V-belts. Ref. to «REMOVAL»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/mechanical/#engine-mechanical-h4dotc-except-sti) , V-belt.
3. Remove the crank pulley. Ref. to «REMOVAL»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/mechanical/#engine-mechanical-h4dotc-except-sti) , Crank Pulley.
4. Remove the timing belt cover. Ref. to «REMOVAL»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/mechanical/#engine-mechanical-h4dotc-except-sti) , Timing Belt Cover.
5. Remove the timing belt. Ref. to «REMOVAL»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/mechanical/#engine-mechanical-h4dotc-except-sti) , 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 «REMOVAL»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/mechanical/#engine-mechanical-h4dotc-except-sti) , 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.

Scheme 82

Scheme 83

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)
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. Ref. to «INSTALLATION»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/mechanical/#engine-mechanical-h4dotc-except-sti) , Cam Sprocket.
6. Install the belt idler No. 2 (C). Tightening torque: 39 N.m (4.0 kgf-m, 28.8 ft-lb)
7. Install the belt idler (B). Tightening torque: 25 N.m (2.5 kgf-m, 18.4 ft-lb)
8. Install the automatic belt tension adjuster (A) with the tension rod held by a pin. Ref. to «AUTOMATIC BELT TENSION ADJUSTER ASSEMBLY AND BELT IDLER»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/mechanical/#engine-mechanical-h4dotc-except-sti) , INSTALLATION, Timing Belt.
9. Install the timing belt. Ref. to «TIMING BELT»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/mechanical/#engine-mechanical-h4dotc-except-sti) , INSTALLATION, Timing Belt.
10. Install the timing belt cover. Ref. to «INSTALLATION»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/mechanical/#engine-mechanical-h4dotc-except-sti) , Timing Belt Cover.
11. Install the crank pulley. Ref. to «INSTALLATION»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/mechanical/#engine-mechanical-h4dotc-except-sti) , Crank Pulley.
12. Install the V-belts. Ref. to «INSTALLATION»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/mechanical/#engine-mechanical-h4dotc-except-sti) , V-belt.
13. Install the radiator. Ref. to «INSTALLATION»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/cooling-system-mechanical/#engine-cooling-system-h4dotc-except-sti) , Radiator.

Scheme 84

1. Check the water pump bearing for smooth rotation.
2. Check the water pump pulley for abnormalities.
3. Make sure the impeller is not abnormally deformed or damaged.
4. Inspect the clearance between impeller and pump case. Clearance between impeller and pump case: Specification 0.5 - 1.5 mm (0.020 - 0.059 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 85

1. Set the vehicle on a lift.
2. Lift up the vehicle.
3. Remove the under cover.
4. Drain the engine coolant. Ref. to «DRAINING OF ENGINE COOLANT»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/cooling-system-mechanical/#engine-cooling-system-h4dotc-except-sti) , REPLACEMENT, Engine Coolant.
5. Disconnect the radiator outlet hose from thermostat cover.
6. Remove the thermostat cover, and then remove the gasket and thermostat.

Scheme 86

Scheme 87

1. Install a gasket to thermostat. NOTE: Use a new gasket.
2. Install the thermostat and thermostat cover. NOTE: Install the parts 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 under cover.
5. Lower the vehicle.
6. Fill engine coolant. Ref. to «FILLING OF ENGINE COOLANT»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/cooling-system-mechanical/#engine-cooling-system-h4dotc-except-sti) , REPLACEMENT, Engine Coolant.

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 the valve lift. Hold the thermostat with a wire or the like to avoid contacting the container.

Starting temperature to open: 76 - 80°C (169 - 176°F)

Full open temperature: 91°C (196°F)

Total valve lift: 9.0 mm (0.354 in) or more

Scheme 88

REMOVAL

Scheme 89

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Scheme 96

Scheme 97

1. Set the vehicle on a lift.
2. Disconnect the ground cable from battery.
3. Lift up the vehicle.
4. Remove the under cover.
5. Remove the heat shield cover from radiator. (AT model)
6. Drain the engine coolant. Ref. to «DRAINING OF ENGINE COOLANT»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/cooling-system-mechanical/#engine-cooling-system-h4dotc-except-sti) , REPLACEMENT, Engine Coolant.
7. Disconnect the connectors of 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) NOTE: Plug the ATF pipe to prevent ATF from leaking.
10. Lower the vehicle.
11. Remove the air intake duct. Ref. to «REMOVAL»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/mechanical/#engine-intake-system-h4dotc-except-sti) , Air Intake Duct.
12. Remove the reservoir tank. Ref. to «REMOVAL»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/cooling-system-mechanical/#engine-cooling-system-h4dotc-except-sti) , Reservoir Tank.
13. Disconnect the radiator inlet hose (A) from the radiator.
14. Disconnect the two coolant filler tank hoses from the radiator.
15. Remove the radiator upper brackets.
16. Move the radiator to the left while lifting it upward.
17. Lift the radiator up and remove the radiator from vehicle.

Scheme 98

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.
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 two coolant filler tank hoses to the radiator.
5. Connect the radiator inlet hose (A).
6. Install the reservoir tank. Ref. to «INSTALLATION»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/cooling-system-mechanical/#engine-cooling-system-h4dotc-except-sti) , Reservoir Tank.
7. Install the air intake duct. Ref. to «INSTALLATION»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/mechanical/#engine-intake-system-h4dotc-except-sti) , Air Intake Duct.
8. Lift up the vehicle.
9. Connect the ATF cooler hoses. (AT model)
10. Connect the radiator outlet hose.
11. Connect the connectors of main fan motor connector (A) and sub fan motor connector (B).
12. Install the heat shield cover to the radiator. (AT model) Tightening torque: 3 N.m (0.3 kgf-m, 2.2 ft-lb)
13. Install the undercover.
14. Lower the vehicle.
15. Connect the ground cable to battery.
16. Fill engine coolant. Ref. to «FILLING OF ENGINE COOLANT»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/cooling-system-mechanical/#engine-cooling-system-h4dotc-except-sti) , REPLACEMENT, Engine Coolant.
17. Check the ATF level. (AT model) Ref. to «INSPECTION»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/automatic-trans/#automatic-transmission-4at-except-sti__inspection) , Automatic Transmission Fluid.

Scheme 99

1. Remove the coolant filler tank cap, fill the coolant filler tank with engine coolant, then install the tester to the installation position of the cap.
2. Apply a pressure of 122 kPa (1.2 kg/cm 2 , 18 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 100

1. Attach the radiator cap tester to radiator cap.
2. Increase pressure until the radiator cap tester gauge pointer stops. Radiator cap is functioning properly if it holds the service limit pressure for 5 - 6 seconds. Replace the cap if it is opened under a pressure less than the service limit value.

Coolant filler tank side

Specification

93 - 123 kPa

(0.95 - 1.25 kg/cm 2 , 14 - 18 psi)

Service limit

83 kPa (0.85 kg/cm 2 , 12 psi)

Radiator side

Specification

122 - 152 kPa

(1.24 - 1.55 kg/cm 2 , 18 - 22 psi)

Service limit

112 kPa (1.14 kg/cm 2 , 16 psi)

Scheme 101

Scheme 102

1. Set the vehicle on a lift.
2. Disconnect the ground cable from battery.
3. Lift up the vehicle.
4. Remove the under cover.
5. Disconnect the main fan motor connector (A).
6. Remove the heat shield cover from radiator. (AT model)
7. Remove the ATF hose from the hose clip of the radiator main fan motor assembly. (AT model)
8. Lower the vehicle.
9. Remove the air intake duct. Ref. to «REMOVAL»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/mechanical/#engine-intake-system-h4dotc-except-sti) , Air Intake Duct.
10. Remove the reservoir tank. Ref. to «REMOVAL»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/cooling-system-mechanical/#engine-cooling-system-h4dotc-except-sti) , Reservoir Tank.
11. Remove the bolts which secure the radiator main fan motor assembly and the over flow pipe.
12. Remove the radiator main fan motor assembly from the upper side of the vehicle.

INSTALLATION

Install in the reverse order of removal.

Tightening torque: 7.5 N.m (0.8 kgf-m, 5.5 ft-lb)

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

Scheme 103

Scheme 104

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

ASSEMBLY

Assemble in the reverse order of disassembly.

Tightening torque: 4.41 N.m (0.45 kgf-m, 3.25 ft-lb)

Tightening torque: 3.4 N.m (0.3 kgf-m, 2.5 ft-lb)

Scheme 105

1. Set the vehicle on a lift.
2. Disconnect the ground cable from battery.
3. Lift up the vehicle.
4. Remove the under cover.
5. Disconnect the sub fan motor connector (B).
6. Remove the heat shield cover from radiator. (AT model)
7. Lower the vehicle.
8. Remove the air intake duct. Ref. to «REMOVAL»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/mechanical/#engine-intake-system-h4dotc-except-sti) , Air Intake Duct.
9. Remove the bolts which secure the radiator sub fan motor assembly and the over flow pipe.
10. Raise the radiator sub fan motor assembly slightly, remove the pin at the lower part of the radiator sub fan motor assembly from the radiator hole, and remove the radiator sub fan motor assembly from the lower side of the vehicle.

Install in the reverse order of removal.

Tightening torque: 7.5 N.m (0.8 kgf-m, 5.5 ft-lb)

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

Scheme 106

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

Scheme 107

Assemble in the reverse order of disassembly.

Tightening torque: 4.41 N.m (0.45 kgf-m, 3.25 ft-lb)

Tightening torque: 3.4 N.m (0.3 kgf-m, 2.5 ft-lb)

1. Pull out the over flow hose (A).
2. Pull out the reservoir tank to the arrow direction while pushing the claw (B).

Scheme 108

Install in the reverse order of removal.

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

Scheme 109

1. Drain approximately 3.0 l (3.2 US qt, 2.6 lmp qt) of coolant. Ref. to «DRAINING OF ENGINE COOLANT»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/cooling-system-mechanical/#engine-cooling-system-h4dotc-except-sti) , REPLACEMENT, Engine Coolant.
2. Disconnect the engine coolant hoses from coolant filler tank.
3. Remove the bolts which secure the coolant filler tank.
4. Disconnect the engine coolant hose which connects the under side of coolant filler tank.
5. Remove the coolant filler tank.

Install in the reverse order of removal.

Tightening torque: 16 N.m (1.6 kgf-m, 11.8 ft-lb)

Scheme 110

ENGINE COOLING SYSTEM TROUBLE REFERENCE

See also:
• COMPULSORY VALVE OPERATION CHECK MODE
• REMOVAL
• REMOVAL
• INSPECTION
• SPECIFICATION
• ADJUSTMENT