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TIMING CHAIN ELONGATION VISUAL CHECK


note When the timing chain elongates more than the specified length, the diagnosis code No. P0012, variable valve timing (VVT) advanced-angle value abnormal, is output. Unless the diagnosis code No. P0012, therefore, is output, the visual check is unnecessary.
note Unless the work using the following scan tool MB991958 is correctly carried out due to the malfunction of ECM, carry out the check whether or not the diagnosis code exists.

  • Storing the learning value regarding the amount of timing chain elongation before the ECM replacement
  • Writing the learning value into the new ECM after the ECM replacement
1.Remove all the ignition coils.
2.Remove the cylinder head cover.
3.Remove the upper chain guide.
caution Always rotate the crankshaft clockwise.

4.Rotating the crankshaft clockwise, align the timing mark of camshaft sprocket with the point on the upper plane of cylinder head shown in the illustration. As a result of this, the No.1 cylinder is positioned at the compression TDC.

5.Look at the inside of timing chain case with one eye in the direction of arrow shown in the illustration. Fix the eye line at the point where the top axis line of the chain elongation indicator at the front side of timing chain case is overlapped with that of the chain elongation indicator at the reverse side of timing chain case.

6.Check the end top point "A" of timing chain cross section surface and the point of chain elongation indicator which is fixed in Step 5. When the end top point "A" of timing chain is positioned at the left-hand side of chain elongation indicator, it is unnecessary to replace the timing chain because the timing chain is within the specified length. When the end top point "A" of timing chain is positioned at the right-hand side of chain elongation indicator, it is necessary to replace the timing chain because the timing chain elongates more than the specified length.
note If the timing chain is extended more than the specified value, the oil pump chain could possibly be extended, too. The oil pump chain, therefore, must be replaced when the timing chain is replaced.

7.Install the upper chain guide.
caution Completely clean the old FIPG remaining in the clearance between the mating parts.
8.After completely removing the liquid gasket sdhering on the timing chain case, cylinder block and cylinder head, degrease them with white gasoline.
caution Install the cylinder head cover within 3 minutes of applying the liquid gasket.
9.Apply a 4 mm diameter bead of liquid gasket to the point shown in the illustration.
Specified sealant: THREE BOND 1217G or equivalent

10.Installing the cylinder head cover, tighten the tightening bolt according to the following procedures.

  1. Temporarily tighten the tightening bolt in the order shown in the illustration.
    Tightening torque: 3.0 ± 1.0 N·m
  2. Tighten the tightening bolt to the specified torque in the order shown in the illustration.
    Tightening torque: 5.5 ± 0.5 N·m
11.Install the ignition coil.
12.Use the scan tool MB991958 to select the timing chain maintenance. Initialize the learning value. Refer to GROUP00, General - Precautions before service - Timing chain maintenance .
note Carry out the initialization even if the amount of timing chain elongation is normal. As a result of this, it is necessary to replace the timing chain before the timing chain interferes with the other components when the next warning lamp illuminates or the diagnosis code No. P0012 is output.