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Home >> Subaru >> 2021 >> WRX Base >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 8 (Engine Mechanical System (2.5L)) >> Valve Clearance >> Inspection

Valve Clearance: Inspection

WARNING: This page is about a different variant/trim than selected.
CAUTION: If engine oil is spilt onto the exhaust pipe, wipe it off with cloth to avoid emission of smoke or causing a fire.
NOTE: Inspection and adjustment of valve clearance should be performed while engine is cold.
  1. Disconnect the ground cable from battery.
  2. Remove the air intake duct. Refer to INTAKE (INDUCTION) (STI)>AIR INTAKE DUCT>REMOVAL .
  3. Remove the bolts (2 places) which secures timing belt cover RH.
    G12437697Courtesy of SUBARU OF AMERICA, INC.
  4. Lift up the vehicle.
  5. Remove the under cover. Refer to EXTERIOR/INTERIOR TRIM>FRONT UNDER COVER>REMOVAL .
  6. Remove the remaining bolts which secure timing belt cover RH together with engine harness cover, then remove the timing belt cover RH.
  7. Lower the vehicle.
  8. When inspecting #1 and #3 cylinders
    1. Remove the air cleaner case. Refer to INTAKE (INDUCTION) (STI)>AIR CLEANER CASE>REMOVAL .
    2. Disconnect the connector (A) from the exhaust camshaft position sensor RH and the connector (B) form the exhaust oil flow control solenoid valve RH.
      G12437698Courtesy of SUBARU OF AMERICA, INC.
    3. Remove the clip (A) which hold the engine harness to the rocker cover RH.
      G08539331Courtesy of SUBARU OF AMERICA, INC.
    4. Remove the ignition coil. Refer to IGNITION(STI)>IGNITION COIL>REMOVAL .
    5. Place a suitable container under the vehicle.
    6. Remove the tape (A) fixing the leak diagnosis connector harness, and disconnect the leak diagnosis connector from the engine harness.
      G12437700Courtesy of SUBARU OF AMERICA, INC.
    7. Unlock the leak diagnosis connector, and disconnect the PCV hose (A) and vacuum hose (B).
      G12437701Courtesy of SUBARU OF AMERICA, INC.
    8. Remove the rocker cover RH.
  9. When inspecting #2 and #4 cylinders
    1. Remove the battery. Refer to STARTING/CHARGING SYSTEMS(STI)>BATTERY>REMOVAL .
    2. Remove the secondary air pump. Refer to EMISSION CONTROL (AUX. EMISSION CONTROL DEVICES) (STI)>SECONDARY AIR PUMP>REMOVAL .
    3. Disconnect the connector (A) from the exhaust camshaft position sensor LH and the connector (B) form the exhaust oil flow control solenoid valve LH.
    4. Remove the clip (C) holding the engine harness.
      G12437702Courtesy of SUBARU OF AMERICA, INC.
    5. Remove the air duct B (B) from the rocker cover LH and the air duct A (A).
      G08539168Courtesy of SUBARU OF AMERICA, INC.
    6. Remove the ignition coil. Refer to IGNITION(STI)>IGNITION COIL>REMOVAL .
    7. Place a suitable container under the vehicle.
    8. Unlock the leak diagnosis connector, and disconnect the PCV hose (A) and vacuum hose (B).
      G11573632Courtesy of SUBARU OF AMERICA, INC.
    9. Remove the rocker cover LH.
  10. Turn the crank pulley clockwise until the round mark on the camshaft sprocket is set to position shown in the figure.
    NOTE: Turn the crank pulley using a socket wrench.
    • Measurement of clearance of #1 cylinder intake valve and #3 cylinder exhaust valve
      G06345045Courtesy of SUBARU OF AMERICA, INC.
    • Measurement of clearance of #2 cylinder exhaust valve and #3 cylinder intake valve
      G06345046Courtesy of SUBARU OF AMERICA, INC.
    • Measurement of clearance of #2 cylinder intake valve and #4 cylinder exhaust valve
      G06345047Courtesy of SUBARU OF AMERICA, INC.
    • Measurement of clearance of #1 cylinder exhaust valve and #4 cylinder intake valve
    G06345048Courtesy of SUBARU OF AMERICA, INC.
  11. Measure the clearance of intake valve and exhaust valve using thickness gauge (A).
    NOTE:
    • Insert a thickness gauge in a direction as horizontal as possible with respect to the valve lifter.
    • Lift up the vehicle, and then measure the exhaust valve clearances.
    • If the measured value is not within the inspection value, take notes of the value in order to adjust the valve clearance later on.

    Valve clearance (inspection value): 

    Intake 

    0.20+0.04-0.06 mm (0.0079+0.0016-0.0024 in)

    Exhaust 

    0.35±0.05 mm (0.0138±0.0020 in)

    G08539175Courtesy of SUBARU OF AMERICA, INC.
  12. If necessary, adjust the valve clearance. Refer to MECHANICAL(STI)>VALVE CLEARANCE>ADJUSTMENT .
  13. After inspection, install the related parts in the reverse order of removal.
    NOTE: Refer to "Camshaft" when installing the rocker cover. Refer to MECHANICAL(STI)>CAMSHAFT>INSTALLATION .

    Tightening torque: 

    6.4 N.m (0.7 kgf-m, 4.7 ft-lb)

    G08539178Courtesy of SUBARU OF AMERICA, INC.

    Tightening torque: 

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

    G12437711Courtesy of SUBARU OF AMERICA, INC.
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