Lexus GX470 2003-06

Timing Belt

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Removal & Installation



  1. Disconnect the negative battery cable.
  2.  
  3. Raise and safely support the vehicle.
  4.  
  5. Remove the oil pan protector and the engine under cover.
  6.  
  7. Drain the cooling system and store the coolant for refilling purposes.
  8.  
  9. Lower the vehicle and remove the battery clamp cover.
  10.  
  11. From the top of the engine, remove the fuel return hose, the engine cover nuts/bolts and the cover.
  12.  
  13. Remove the air cleaner and the intake air connector assembly.
  14.  
  15. Remove the cooling fan pulley by performing the following procedures:
    1. Loosen the 4 fan clutch-to-fan pulley nuts.
    2.  
    3. Using a box-end wrench on the serpentine drive belt tensioner bolt, rotate the tensioner counterclockwise and remove the drive belt.
      NOTE
      The serpentine drive belt tensioner bolt is a left-hand thread.

    4.  
    5. Remove the fan clutch-to-fan pulley nuts, the fan, the clutch assembly and the fan pulley.
    6.  

  16.  
  17. Remove the radiator by performing the following procedures:
    1. Disconnect the upper, lower and reservoir hoses from the radiator.
    2.  
    3. Disconnect and plug the automatic transmission oil cooler at the radiator. Disconnect the automatic transmission oil cooler hoses from the fan shroud clamp.
    4.  
    5. Remove the radiator reservoir tank.
    6.  
    7. Remove the fan shroud-to-radiator bolts and the shroud.
    8.  
    9. Remove the 2 upper radiator-to-chassis nuts.
    10.  
    11. Remove the middle radiator-to-chassis nut/bolts and brackets.
    12.  
    13. Carefully, lift the radiator from the vehicle.
    14.  

  18.  
  19. Remove the serpentine drive belt idler pulley bolt, cover plate and pulley.
  20.  
  21. Remove the right side (No. 3) timing belt cover.
  22.  
  23. Remove the left side (No. 3) timing belt cover by performing the following procedures:
    1. Disconnect the engine wire from both wire clamps.
    2.  
    3. Disconnect the camshaft position sensor wire from the wire clamp on the left-side (No.3) timing belt cover.
    4.  
    5. Disconnect the sensor connector from the connector bracket.
    6.  
    7. Disconnect the sensor connector.
    8.  
    9. Remove the wire grommet from the left-side (No. 3) timing belt cover.
    10.  
    11. Remove the oil cooler tube bolts and tube.
    12.  

  24.  
  25. Remove the middle (No. 2) timing belt cover bolts and cover.
  26.  
  27. Remove the cooling fan bracket nuts/bolts and bracket.
    NOTE
    If reusing the timing belt, make sure that there are 3 installation marks on the belt; if there are none, install them.

  28.  
  29. Using the Crankshaft Pulley Holding tool 09213-70010, Bolt tool 90105-08076 and Companion Flange Holding tool 09330-00021, or equivalent, loosen the crankshaft pulley bolt.
  30.  
  31. Position the No. 1 cylinder to approximately 50 degrees After Top Dead Center (ATDC) of the compression stroke by performing the following procedures:
    1. Rotate the crankshaft pulley (CLOCKWISE) to align its groove with the timing mark -0- on the lower (No. 1) timing belt cover.
    2.  
    3. Check that the camshaft sprocket timing marks are aligned with the rear timing belt plate marks; if not, rotate the crankshaft 1 revolution (360 degrees).
    4.  
    5. Rotate the crankshaft pulley approximately 50 degrees (CLOCKWISE) and align the crankshaft pulley timing mark between the centers of the crankshaft pulley bolt and the idler pulley bolt.
      WARNING
      If the timing belt is disengaged, having the crankshaft pulley in the wrong angle can cause the valve to come into contact with the piston when removing the camshaft pulley.

    6.  

  32.  
  33. Remove the crankshaft pulley bolt.
    NOTE
    If reusing the timing belt and the installation marks have disappeared, place new installation marks on the timing belt to match the camshaft timing sprocket marks.


    NOTE
    To avoid meshing the timing sprocket and the timing belt, secure one with a string; then, place matchmarks on the timing belt and the right-side camshaft timing sprocket.

  34.  
  35. Remove the timing belt tensioner bolts and the tensioner.
  36.  
  37. Using the Camshaft Holding tool 09960-10010, or equivalent, slightly turn the left-side camshaft sprocket clockwise to loosen the tension spring. Then, disconnect the timing belt from the camshaft sprockets.
  38.  
  39. Remove the alternator by performing the following procedures:
    1. Disconnect the electrical connector from the alternator.
    2.  
    3. Remove the rubber cap/nut and disconnect the battery wire from the alternator.
    4.  
    5. Disconnect the wire clamp from the alternator cord clip.
    6.  
    7. Remove the alternator-to-engine nuts/bolts and the alternator.
    8.  

  40.  
  41. Remove the serpentine drive belt tensioner nuts/bolts and the tensioner.
  42.  
  43. Using the Crankshaft Puller Assembly tool 09950-50012, or equivalent, press the crankshaft pulley from the crankshaft.
    WARNING
    DO NOT rotate the crankshaft pulley.

  44.  
  45. Remove the lower (No. 1) timing belt cover bolts and the cover.
  46.  
  47. Remove the timing belt guide, spacer and the timing belt.

    Click image to see an enlarged view

    Fig. Exploded view of vehicle components for timing belt replacement-LX470



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    Fig. Exploded view of vehicle components for timing belt replacement-GX470



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    Fig. Exploded view of upper timing belt covers



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    Fig. Exploded view of upper timing sprockets and components



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    Fig. Exploded view of lower timing belt cover, sprockets and components



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    Fig. Alignment of timing belt with the timing sprockets



    Click image to see an enlarged view

    Fig. Aligning of crankshaft pulley timing mark with the center line of the crankshaft pulley bolt and the idler pulley bolt



    Click image to see an enlarged view

    Fig. Securing the timing belt with string and matchmarking the camshaft with the timing belt



    Click image to see an enlarged view

    Fig. Installing the timing belt on the crankshaft sprocket



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    Fig. Securing the timing belt tensioner pushrod



    Click image to see an enlarged view

    Fig. Checking the TDC alignment marks after rotating the crankshaft 2 revolutions

  48.  

To install:


NOTE
With the timing belt removed, this is a perfect opportunity to inspect and/or replace the water pump.

  1. Inspect the timing belt tensioner by performing the following procedures:
    1. Inspect the seal for leakage; if leakage is suspected, replace the tensioner.
    2.  
    3. Using both hands to hold the tensioner facing upward, strongly press the pushrod against a solid surface. If the pushrod moves, replace the tensioner.
      WARNING
      Never hold the tensioner with the pushrod facing downward.

    4.  
    5. Measure the pushrod protrusion from the housing end, it should be 0.413-0.453 in. (10.5-11.5mm). If the protrusion is not as specified, replace the tensioner.
    6.  

  2.  
  3. Temporarily install the timing belt by performing the following procedures:
    1. Align the timing belt-s installation mark with the crankshaft timing sprocket.
    2.  
    3. Install the timing belt on the crankshaft timing sprocket, the No. 1 idler pulley and the No. 2 idler pulley.
    4.  

  4.  
  5. Install the gasket to the timing belt cover spacer and install the cover spacer.
  6.  
  7. Install the timing belt guide with the cup side facing outward.
  8.  
  9. Install the lower (No. 1) timing belt cover.
  10.  
  11. Install the crankshaft pulley by performing the following procedures:
    1. Align the crankshaft pulley with the crankshaft key.
    2.  
    3. Using the Crankshaft Installer tool 09223-46011, or equivalent, and a hammer, tap the crankshaft pulley into position.
    4.  

  12.  
  13. Install the serpentine drive belt tensioner and torque the tensioner-to-engine bolts to 12 ft. lbs. (16 Nm).
    NOTE
    To install the serpentine drive belt tensioner, use a bolt 4.18 in. (106mm) in length.

  14.  
  15. Check that the crankshaft pulley-s timing mark is aligned with the centers of the idler pulley and crankshaft pulley bolts.
  16.  
  17. Install the alternator and torque the alternator-to-engine nuts/bolts to 29 ft. lbs. (39 Nm). Connect the alternator-s electrical connectors and clip.
  18.  
  19. Install the timing belt to the left-side camshaft by performing the following procedures:
    1. Rotate the left-side camshaft pulley to align the timing belt installation mark with the camshaft sprocket-s timing mark and slide the belt onto the camshaft timing sprocket.
    2.  
    3. Using the Camshaft Holding tool 09960-10010, or equivalent, slightly turn the left-side camshaft sprocket counterclockwise to place tension on the timing belt between the crankshaft sprocket and the camshaft sprocket.
    4.  

  20.  
  21. Rotate the right-side camshaft pulley to align the timing belt installation mark with the camshaft sprocket-s timing mark and slide the belt onto the camshaft timing sprocket.
  22.  
  23. Using a vertical press, slowly press the pushrod into the housing using 200-2205 lbs. (981-9807 N) until the holes align, then, install a 1.27mm Allen® wrench to secure the pushrod and release the press. Install the dust boot on the tensioner housing.
  24.  
  25. Install the timing belt tensioner and torque the bolts to 19 ft. lbs. (26 Nm).
  26.  
  27. Using a pair of pliers, remove the Allen® wrench from the tensioner housing.
  28.  
  29. Check the valve timing by performing the following procedure:
    1. Temporarily install the crankshaft pulley bolt.
    2.  
    3. Slowly, rotate the crankshaft pulley 2 revolutions (CLOCKWISE) and realign the TDC marks.
      NOTE
      If the pulley/sprocket timing marks do not realign, remove the timing belt and reinstall it.

    4.  

  30.  
  31. Using the Crankshaft Pulley Holding tool 09213-70010, Bolt tool 90105-08076 and Companion Flange Holding tool 09330-00021, or equivalent, torque the crankshaft pulley bolt to 181 ft. lbs. (245 Nm).
  32.  
  33. Install the cooling fan bracket and torque the 12mm (head size) bolt to 12 ft. lbs. (16 Nm) and the 14mm (head size) bolt to 24 ft. lbs. (32 Nm).
  34.  
  35. Install the air conditioning compressor.
  36.  
  37. Install the middle (No. 2) timing belt cover and torque the bolts to 12 ft. lbs. (16 Nm).
  38.  
  39. Install the upper right-side (No. 3) timing belt cover and torque the bolts to 66 inch lbs. (7.5 Nm).
  40.  
  41. Install the upper left-side (No. 3) timing belt cover by performing the following procedures:
    1. Install the oil cooler tube and bolt.
    2.  
    3. Feed the Camshaft Position Sensor (CPS) through the left-side (No. 3) timing belt cover hole.
    4.  
    5. Install the left-side (No. 3) timing belt cover and torque the bolts to 66 inch lbs. (7.5 Nm).
    6.  
    7. Install the wire grommet to the left-side (No. 3) timing belt cover.
    8.  
    9. Install the sensor connector to the connector bracket and connect the sensor connector.
    10.  
    11. Install the sensor wire and the engine wire to the clamps on the left-side (No. 3) timing belt cover.
    12.  

  42.  
  43. Install the drive belt idler pulley and cover plate; then, torque the pulley bolt to 27 ft. lbs. (37 Nm).
  44.  
  45. To complete the installation, reverse the removal procedures.
  46.  
  47. Refill the cooling system and connect the negative battery cable.
  48.  

 
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