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Home >> Nissan-Datsun >> 2008 >> Sentra SL >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 2 (Engine Mechanical (Qr25DE)) >> Cylinder Block >> Disassembly and Assembly >> Disassembly

Disassembly and Assembly: Disassembly

WARNING: This page is about a different variant/trim than selected.
  1. Remove the engine and transaxle as an assembly from the vehicle, and separate the transaxle from the engine. Refer to "REMOVAL AND INSTALLATION ".
  2. Mount the engine on a suitable engine stand.
  3. Drain any remaining engine oil and coolant from the engine.
  4. Remove the following components and associated parts.
  5. Remove the knock sensor.
    CAUTION: Carefully handle the sensor and do not drop the sensor.
  6. Remove crankshaft position sensor (POS).
    CAUTION:
    • Avoid impacts such as a dropping.
    • Do not disassemble.
    • Keep it away from metal particles.
    • Do not place sensor close to magnetic materials.
      Fig 1: Crankshaft Position Sensor (POS) With Torque Specifications
      G04924888Courtesy of NISSAN MOTOR CO., U.S.A.
  7. Remove the flywheel (M/T models) or drive plate (CVT models). Hold the crankshaft with a stopper plate and use a suitable tool to remove the bolts.
    CAUTION:
    • Be careful not to damage the flywheel contact surface for the clutch disc.
    NOTE:
    • The flywheel two-block construction allows movement in response to transmission side pressure, or when twisted in its rotational direction, therefore, some amount of noise is normal.
      Fig 2: Securing Flywheel
      G04885830Courtesy of NISSAN MOTOR CO., U.S.A.
  8. Remove pilot converter using Tool (CVT models).
    Fig 3: Removing Pilot Converter (A/T Models)
    G04885831Courtesy of NISSAN MOTOR CO., U.S.A.
  9. Remove the piston and connecting rod assemblies.
    1. Position the crankshaft and corresponding connecting rod, to be removed, to the bottom dead center stroke.
    2. Remove the connecting rod cap. Number the cap so it can be assembled in the same position.
    3. Using a hammer handle or similar tool, push the piston and connecting rod assembly out of the top of the cylinder block. Number the piston and rod so it can be assembled in the same position.
      • Before removing the piston and connecting rod assembly, check the connecting rod side clearance. Refer to "CONNECTING ROD SIDE CLEARANCE ".
        Fig 4: Pushing Piston And Connecting Rod Assembly
        G04885832Courtesy of NISSAN MOTOR CO., U.S.A.
  10. Remove the connecting rod bearings. If reusing, number them so they can be assembled in the same position and direction.
    CAUTION:
    • When removing them, note the installation position. Keep them in the correct order.
  11. Remove the piston rings from the piston.
    • Use a piston ring expander.
    CAUTION:
    • When removing the piston rings, be careful not to damage the piston. 
    • Be careful not to damage piston rings by expanding them excessively, if reusing them. 
    • Before removing the piston rings, check the piston ring side clearance. Refer to "PISTON RING SIDE CLEARANCE ".
      Fig 5: Identifying Piston Rings Expander
      G04878457Courtesy of NISSAN MOTOR CO., U.S.A.
  12. Remove the piston from the connecting rod as follows.
    1. Using a snap ring pliers, remove the two snap rings.
      Fig 6: Identifying Snap Ring
      G04899811Courtesy of NISSAN MOTOR CO., U.S.A.
    2. Heat the piston to 60° - 70°C (140° - 158°F) with a heat gun, or equivalent.
      Fig 7: Heating Piston
      G04899812Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Push out piston pin with a punch of an outer diameter of approximately 19 mm (0.75 in).
      Fig 8: Pushing Out Piston Pin
      G04878460Courtesy of NISSAN MOTOR CO., U.S.A.
  13. Remove the lower cylinder block bolts.
    • Before loosening the lower cylinder block bolts, measure the crankshaft side clearance. Refer to "CRANKSHAFT SIDE CLEARANCE ".
    • Loosen them in the order as shown to remove them.
      Fig 9: Cylinder Block Bolt With Loosening Sequence
      G04885837Courtesy of NISSAN MOTOR CO., U.S.A.
  14. Remove the lower cylinder block.
    • Cut the Silicone RTV Sealant and remove the lower cylinder block from the cylinder block, using Tool.

      Seal cutter KV10111100 (J-37228) 

      CAUTION: Be careful not to damage the mounting surface.
  15. Remove the crankshaft.
    CAUTION:
    • Do not damage or deform the signal plate while mounted on the crankshaft.
    • When setting the crankshaft on a flat surface, use a block of wood to avoid interference between the signal plate and the surface.
    • Do not remove signal plate unless it is necessary.
  16. Pull the rear oil seal out of the rear end of the crankshaft.
    CAUTION: Do not to damage the crankshaft or cylinder block when removing the rear oil seal.
    NOTE: When replacing the rear oil seal without removing the cylinder block, use a screwdriver to pull it out from between crankshaft and block.
    Fig 10: Identifying Crankshaft Signal Plate
    G04885838Courtesy of NISSAN MOTOR CO., U.S.A.
  17. Remove the main bearings and thrust bearings from the cylinder block and lower cylinder block.
    CAUTION: Identify and number the bearings, if reusing them, so that they are assembled in the same position and direction.
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