Subaru Tribeca 2006

Spark Plugs

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Inspection



Check the electrodes and inner and outer ceramic insulator of plugs, noting the type of deposits and the degree of electrode erosion.

Click image to see an enlarged view

Fig. Checking (A) spark plug gap, (B) carbon accumulation or wear, (C) cracks, (D) damage, (E) damaged gasket

  1. Normal: Brown to grayish-tan deposits and slight electrode wear indicate correct spark plug heat range.

    Click image to see an enlarged view

    Fig. Identifying normal spark plug wear

  2.  
  3. Carbon fouled: Dry fluffy carbon deposits on insulator and electrode are mostly caused by slow speed driving in the city, weak ignition, too rich fuel mixture and dirty air cleaner.

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    Fig. Identifying carbon fouled spark plug

  4.  
  5. Oil fouled: Wet black deposits show oil entrance into the combustion chamber through worn rings and pistons or excessive clearance between valve guides and stems.

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    Fig. Identifying oil fouled spark plug

  6.  
  7. Overheating: White or light gray insulator with black or brown spots and bluish burnt electrodes indicate engine overheating. Moreover, the appearance results from incorrect ignition timing, loose spark plugs, wrong selection of fuel, hotter range plug, etc.

    Click image to see an enlarged view

    Fig. Identifying overheated spark plug

  8.  

Removal & Installation




CAUTION
All spark plugs installed on an engine must be of the same heat range.

Left Side
  1. Remove the collector cover.
  2.  
  3. Remove the battery and battery carrier.
  4.  
  5. Remove the (A) bracket.
  6.  
  7. Disconnect the (B) connector from ignition coil.
  8.  
  9. Remove the ignition coil.
    NOTE
    Turn the no. 6 ignition coil to remove it.



    Click image to see an enlarged view

    Fig. Removing bracket and connector from the ignition coil-left side

  10.  
  11. Remove the spark plug with a spark plug socket.

    Click image to see an enlarged view

    Fig. Removing the spark plug with a spark plug socket-left side

  12.  

To install:

  1. To install reverse the removal procedures
    NOTE
    The tightening torque described above should be applied to only new spark plugs without oil on their threads. In case their threads are lubricated, the torque should be reduced by approximately 1 / 3 of the specified torque in order to avoid over-stressing.



    Tighten the spark plug to 15 ft. lbs. (21 Nm)
     
    Tighten the ignition coil to 12 ft. lbs. (16 Nm)
     

  2.  

Right Side
  1. Remove the collector cover.
  2.  
  3. Disconnect the ground cable from battery.
  4.  
  5. Remove the air cleaner case.
  6.  
  7. Remove the (A) bracket.
  8.  
  9. Disconnect the (B) connector from ignition coil.
  10.  
  11. Remove the ignition coil.
    NOTE
    Turn the #5 ignition coil to remove it.



    Click image to see an enlarged view

    Fig. Removing bracket and connector from ignition coil-right side

  12.  
  13. Remove the spark plug with a spark plug socket.

    Click image to see an enlarged view

    Fig. Remove the spark plug with a spark plug socket-right side



    Click image to see an enlarged view

    Fig. Identifying (A) ratchet handle, (B) extension bar, (C) universal joint, (D) spark plug socket

  14.  

To install:

To install reverse the removal procedures



Tighten the spark plug to 15 ft. lbs. (21 Nm)
 
Tighten the ignition coil to 12 ft. lbs. (16 Nm)
 


NOTE
The tightening torque described above should be applied to only new spark plugs without oil on their threads. In case their threads are lubricated, the torque should be reduced by approximately 1 / 3 of the specified torque in order to avoid over-stressing.

 
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