Engine Intake System (H4DOTC) (Except Sti): Diagnosis Subaru Impreza GH

INSPECTION

Replace if excessively damaged or dirty.

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Scheme 306

1. Disconnect the ground cable from battery.
2. Remove the air intake duct. Ref. to «REMOVAL»(ref-357235-S10313590332010031100000) , Air Intake Duct.
3. Disconnect the connector from air flow and intake air temperature sensor.
4. Loosen the clamp (B) which connects the air intake boot and intake duct.
5. Remove the clip (C) from the air cleaner case (front).
6. Remove the air cleaner case (rear) and air intake boot.
7. Remove the air cleaner element.
8. Remove the bolt (A) and-nut (B) which secure the air cleaner case (front) to the body.
9. Remove the air cleaner case (front).

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Scheme 308

1. Install the bolt (A) and nut (B) which secure the air cleaner case (front) to the body. Tightening torque: Bolt (A) 6 N.m (0.6 kgf-m, 4.4 ft-lb) Nut (B) 7.5 N.m (0.8 kgf-m, 5.5 ft-lb)
2. Install the air cleaner element.
3. Install the air cleaner case (rear) and air intake boot. NOTE: When installing the air cleaner case (rear), align the protrusion of the air cleaner case (rear) to the hole on the air cleaner case (front) to install. Tightening torque: 2.5 N.m (0.3 kgf-m, 1.8 ft-lb)
4. Install the clip (B) to the air cleaner case (front).
5. Connect the connector (A) to the mass air flow and intake air temperature sensor.
6. Install the air intake duct. Ref. to «INSTALLATION»(ref-357235-S12040137862010031100000) , Air Intake Duct.
7. Connect the ground cable to battery.

Check for cracks or loose connections.

1. Check for cracks or loose connections.
2. Inspect that no foreign objects in the air intake duct.

Check for cracks or loose connections.

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1. Set the vehicle on a lift.
2. Disconnect the ground cable from battery.
3. Lift up the vehicle.
4. Drain approximately 3.0 C (3.2 US qt, 2.6 Imp qt) of coolant. Ref. to «DRAINING OF ENGINE COOLANT»(ref-357239-S42364927112010031100000) , REPLACEMENT, Engine Coolant.
5. Lower the vehicle.
6. Remove the intercooler. Ref. to «REMOVAL»(ref-357235-S29312200482010031100000) , Intercooler.
7. Remove the center exhaust pipe. Ref. to «REMOVAL»(ref-357260-S26748740802010031100000) , Center Exhaust Pipe.
8. Lower the vehicle.
9. Remove the joint pipe from the turbocharger.
10. Disconnect the engine coolant hoses from coolant filler tank.
11. Disconnect the air control hose (A), and loosen the clamp holding the turbocharger to the intake duct. Except for WRX-SS model WRX-SS model
12. Remove the oil inlet pipe from the turbocharger. Except for WRX-SS model WRX-SS model
13. Disconnect the engine coolant hose from the water pipe.
14. Disconnect the oil outlet hose from the oil outlet pipe, and remove the turbocharger.
15. Remove the turbocharger stay.

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1. Install the turbocharger stay. Tightening torque: T1:33 N.m (3.4 kgf-m, 24.3 ft-lb) T2:42.5 N.m (4.3 kgf-m, 31.3 ft-lb)
2. Connect the oil outlet hose to the oil outlet pipe.
3. Connect the engine coolant hoses to the water pipe.
4. Install the oil inlet pipe to turbocharger. Except for WRX - SS model Tightening torque: T1: 5 N.m (0.5 kgf-m, 3.7 ft-lb) T2: 16 N.m (1.6 kgf-m, 11.8 ft-lb) T3: 20 N.m (2.0 kgf-m, 14.8 ft-lb) WRX-SS model Tightening torque: T1: 16 N.m (1.6 kgf-m, 11.8 ft-lb) T2: 20 N.m (2.0 kgf-m, 14.8 ft-lb)
5. Connect the air control hose (A), and install the turbocharger to the intake duct. Tightening torque: 3 N.m (0.3 kgf-m, 2.2 ft-lb) Except for WRX-SS model WRX-SS model
6. Connect the engine coolant hoses to the coolant filler tank.
7. Install the joint pipe to turbocharger. NOTE: Replace the gasket with a new part. Tightening torque: 42.5 N.m (4.3 kgf-m, 31.3 ft-lb)
8. Lift up the vehicle.
9. Install the center exhaust pipe. Ref. to «INSTALLATION»(ref-357260-S05562151172010031100000) , Center Exhaust Pipe.
10. Lower the vehicle.
11. Install the intercooler. Ref. to «INSTALLATION»(ref-357235-S05398122832010031100000) , Intercooler.
12. Connect the ground cable to battery.
13. Fill engine coolant. Ref. to «FILLING OF ENGINE COOLANT»(ref-357239-S07197404722010031100000) , REPLACEMENT, Engine Coolant.

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Scheme 323

1. Except for WRX-SS model Remove the intercooler. Ref. to «REMOVAL»(ref-357235-S29312200482010031100000) , Intercooler. Remove the turbocharger upper cover. Remove the boost hose (B) from the waste gate actuator (A) of the turbocharger, and connect the Mighty Vac to the waste gate actuator (A). Pressurize slowly with the Mighty Vac, and measure the pressure when the control rod stroke (D) becomes 1 mm (0.04 in). If it is not within the standard, replace the turbocharger assembly. CAUTION: Do not pressurize over 56.0 kPa (0.57 kgf/cm 2 , 8.12 psi) to prevent damaging the waste gate actuator. Operating pressure (Control rod stroke 1 mm (0.04 in)): Standard 44.0 - 46.6 kPa (0.45 - 0.48 kgf/cm 2 , 6.38 - 6.76 psi) After inspection, install the related parts in the reverse order of removal. Tightening torque: 7.5 N.m (0.8 kgf-m, 5.5 ft-lb)

Scheme 324

1. WRX-SS model Remove the intercooler. Ref. to «REMOVAL»(ref-357235-S29312200482010031100000) , Intercooler. Remove the turbocharger upper cover. Remove the boost hose (B) from the waste gate actuator (A) of the turbocharger, and connect the Mighty Vac to the waste gate actuator (A). Pressurize slowly with the Mighty Vac, and measure the pressure when the control rod stroke (D) becomes 2 mm (0.08 in). If it is not within the standard, replace the turbocharger assembly. CAUTION: Do not pressurize over 89.9 kPa (0.92 kgf/cm 2 , 13.0 psi) to prevent damaging the waste gate actuator. Operating pressure (Control rod stroke 2 mm (0.08 in)): Standard 74.7 - 80.8 kPa (0.76 - 0.82 kgf/cm 2 , 10.8 - 11.7 psi) After inspection, install the related parts in the reverse order of removal. Tightening torque: 7.5 N.m (0.8 kgf-m, 5.5 ft-lb)