Toyota Prius 2002-06

Valve Lash (Clearance) Adjustment

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NOTE
Inspect and adjust the valve clearance when the engine is cold.

  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Set the No. 1 cylinder to TDC/compression.

    Turn the crankshaft pulley until its timing notch and timing mark 0 of the chain cover are aligned.

    Click image to see an enlarged view

    Fig. Check that both timing marks on the camshaft timing sprocket and camshaft timing gear are facing upward-1.5L hybrid engine

     
    Check that both timing marks on the camshaft timing sprocket and camshaft timing gear are facing upward as shown in the illustration. If not, turn the crankshaft 1 complete revolution (360 degrees) and align the marks as above.

    Click image to see an enlarged view

    Fig. Check the clearance of the valves indicated (No. 1 cylinder)-1.5L hybrid engine

     

  4.  
  5. Check the valves indicated in the illustration. Using a feeler gauge, measure the clearance between the valve lifter and camshaft.

    Standard intake valve clearance (Cold): 0.007-0.009 inch (0.17-0.23mm)
     
    Standard exhaust valve clearance (Cold): 0.011-0.013 inch (0.27-0.33mm)
     

  6.  
  7. Record any out-of-specification valve clearance measurements. They will be used later to determine the required replacement lifter.
  8.  
  9. Turn the crankshaft 1 complete revolution until its timing notch and timing mark 0 of the chain cover are aligned.

    Click image to see an enlarged view

    Fig. Check the clearance of the following valves (No. 4 cylinder)-1.5L hybrid engine

  10.  
  11. Check the valves indicated in the illustration. Using a feeler gauge, measure the clearance between the valve lifter and camshaft.

    Standard intake valve clearance (Cold): 0.007-0.009 inch (0.17-0.23mm)
     
    Standard exhaust valve clearance (Cold): 0.011-0.013 inch (0.27-0.33mm)
     

  12.  
  13. Record any out-of-specification valve clearance measurements. They will be used later to determine the required replacement lifter.
  14.  
  15. Set the No. 1 cylinder to TDC/compression.
  16.  
  17. Turn the crankshaft pulley until its timing notch and timing mark 0 of the chain cover are aligned.
  18.  
  19. Check that both timing marks on the camshaft timing sprocket and valve timing controller assembly are facing upward. If not, turn the crankshaft 1 complete revolution (360 degrees) and align the marks as above.
  20.  
  21. Put paint marks on the timing chain where the timing marks of the camshaft timing sprocket and the camshaft timing gear are located.
  22.  
  23. Using an 8mm hexagon wrench, remove the screw plug.
  24.  
  25. Insert a screwdriver into the service hole of the chain tensioner to hold the stopper plate of the chain tensioner at an upward position. Lifting up the stopper plate of the chain tensioner unlocks the plunger.
  26.  
  27. Keeping the stopper plate of the chain tensioner lifted, slightly rotate the hexagonal lobe of the No. 2 camshaft to the right with an adjustable wrench so the plunger of the chain tensioner is pushed. When the camshaft No. 2 is slightly rotated to the right, the plunger is pushed.
  28.  
  29. Keeping the adjustable wrench installed, remove the screwdriver with the plunger pushed. Do not move the adjustable wrench.
    NOTE
    Removing the screwdriver lowers the stopper plate and locks the plunger.

  30.  
  31. Insert a 0.118 inch (3.0mm) diameter bar into the hole of the stopper plate with the stopper plate of the chain tensioner lowered and locked. If the bar cannot be inserted into the hole of the stopper plate, rotate the No. 2 camshaft slightly to the left and right. Then that bar can be inserted easily.
  32.  
  33. Secure the bar with tape.
  34.  
  35. Hold the hexagonal lobe of the camshaft No. 2 with the adjustable wrench.
  36.  
  37. Using SST 09023-38400, loosen the bolt.

    Click image to see an enlarged view

    Fig. Remove the 11 bearing cap bolts in the sequence-1.5L hybrid engine

  38.  
  39. Using several steps, uniformly loosen and remove the 11 bearing cap bolts in the sequence shown in the illustration. Then remove the 5 bearing caps. Loosen each bolt uniformly, keeping the camshaft level.
  40.  
  41. Remove the flange bolt with the No. 2 camshaft lifted up. Then detach the No. 2 camshaft and the camshaft timing sprocket.

    Click image to see an enlarged view

    Fig. Remove the 8 bearing cap bolts in the sequence-1.5L hybrid engine

  42.  
  43. Using several steps, uniformly loosen and remove the 8 bearing cap bolts in the sequence shown in the illustration. Then remove the 4 bearing caps. Loosen each bolt uniformly, keeping the camshaft level.
  44.  
  45. Hold the timing chain with one hand, and remove the camshaft and the camshaft timing gear assembly.

    Click image to see an enlarged view

    Fig. Tie the timing chain with a string-1.5L hybrid engine

  46.  
  47. Tie the timing chain with a string as shown in the illustration.
    CAUTION
    Be careful not to drop anything inside the timing chain cover.

  48.  
  49. Remove the valve lifters.
  50.  
  51. Using a micrometer, measure the thickness of the removed lifter.
  52.  
  53. Calculate the thickness of a new lifter so that the valve clearance comes within the specified value.
  54.  
  55. Select a new lifter with the thickness as close to the calculated values as possible.
    NOTE
    Lifters are available in 35 sizes in increments of 0.0008 inch (0.020mm), from 0.1992 inch (5.060mm) to 0.2260 inch (5.740mm).



    EXAMPLE: (Intake) Measured valve clearance = 0.0158 inch (0.40mm)
     
    0.0158 inch (0.40mm) - 0.0079 inch (0.20mm) = 0.0079 inch (0.20mm) (Measured - Specification = Excess clearance)
     
    Used lifter measurement = 0.2067 inch (5.25mm)
     
    0.0079 inch (0.20mm) + 0.2067 inch (5.25mm) = 0.2146 inch (5.45mm) (Excess clearance + Used lifter = Ideal new lifter)
     
    Closest new lifter = 5.45 mm (0.2146 in.); select lifter (0.2150 inch (5.46mm))
     

  56.  

 
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