Timing Chain Removal Note

WARNING: This page is about a different car, the 2016 Mazda CX-5. However, it is still accessible from the selected car via links, so may be relevant.

Release the tension on the timing chain using the following procedure:
NOTE:
- Release the tension on the timing chain by securing the timing chain tensioner arm through the service hole on the engine front cover.
1. Remove the blind plugs (upper and lower) on the engine front cover service holes.
  
  Fig 1: Removing Blind Plugs (Upper And Lower) On Engine Front Cover Service Holes
  Courtesy of MAZDA MOTORS CORP.
2. Insert an M6 bolt (35-60 mm {1.4-2.3 in} length with thread to the end) to the upper service hole and tighten it until it contacts the tensioner arm, then loosen it approx. 180 degrees (set the bolt so that it sits slightly in front of the tensioner arm).
  
  Fig 2: Inserting M6 Bolt To Upper Service Hole
  Courtesy of MAZDA MOTORS CORP.
  NOTE:
  - The bolt contacts the tensioner arm when it is inserted approx. 20 mm {0.79 in} .
  - Hold the exhaust camshaft using a wrench on the cast hexagon and move it back and forth a few times as shown in the figure. This will drain the oil from the chain tensioner and make the following servicing easier.
  Fig 3: Holding Exhaust Camshaft Using Wrench On Cast Hexagon
  Courtesy of MAZDA MOTORS CORP.
3. Insert a precision screwdriver into the lower service hole.
4. While moving the exhaust camshaft back and forth in the direction of the arrow using a wrench on the cast hexagon, press down the link plate of the timing chain tensioner using a precision screwdriver and release the plunger lock.
  
  Fig 4: Moving Exhaust Camshaft Back And Forth Using Wrench On Cast Hexagon
  Courtesy of MAZDA MOTORS CORP.
  
  Fig 5: Inserting Precision Screwdriver Into Lower Service Hole
  Courtesy of MAZDA MOTORS CORP.
  NOTE:
  - When moving the exhaust camshaft back and forth, the timing chain pushes the plunger in the chain tensioner making it easier to operate the link plate.
5. With the plunger lock released, rotate the exhaust camshaft clockwise until the timing chain loosens.
  
  Fig 6: Rotating Exhaust Camshaft Clockwise
  Courtesy of MAZDA MOTORS CORP.
6. With the chain loosened, tighten the M6 bolt in the upper service hole so that the bolt is inserted approx. 5 mm {0.2 in} additionally to secure the tensioner arm.
  NOTE:
  - By rotating the exhaust camshaft clockwise, the timing chain pushes the tensioner arm and the rib position deviates. The entire tensioner arm can be secured by hooking the bolt onto the deviated rib.
    
    Fig 7: Securing Tensioner Arm
    Courtesy of MAZDA MOTORS CORP.
  - If the bolt cannot be inserted approx. 5 mm {0.2 in} , the plunger lock of the chain tensioner may not release, or the chain may not loosen enough. Return the bolt to the original position and restart the procedure from Step (3).
7. After securing the tensioner arm, remove the chain guide (No. 1).