How to Replace timing chain on Mercedes C250 CDI 4Matic W204 2008-

Special tools

• Balancer shaft alignment tool – No.651589026300.
• Camshaft alignment tools – No.651589014000.
• Crankshaft pulley holding tool – No.651589004000 or 651589084000.
• Timing chain link separator (item 1) – No.602589023300.
• Timing chain link separator (item 2) – No.602589046300.
• Timing chain link separator (item 3) – No.602589046301.
• Timing chain link installer – No.642589003300.
• Timing chain link installer die kit – No.651589046300.
• Timing chain to camshaft sprocket holder – No.651589034000.
• Tool case – No.602589009800.

General precautions

• Disconnect battery earth lead.
• Remove glow plugs to ease turning engine.
• Turn engine in normal direction of rotation (unless otherwise stated).
• Observe tightening torques.
• If fitted: Mark position of crankshaft position (CKP) sensor before removal.
• Do NOT turn crankshaft via camshaft or other sprockets.
• Do NOT turn crankshaft or camshaft with timing chain removed.

Valve timing procedures

NOTE: Timing chain can be changed without dismantling engine. Using the tools listed above, the new chain can be linked to the old, passed round the sprockets and then joined.

• Removal/installation of timing chain and gears requires:
  • Engine removal.
  • Flywheel removal.
  • Sump removal.

NOTE: Timing chain and gears located at rear of engine.

• Check camshaft timing:
  • Engine at TDC on No.1 cylinder [1] .
  • Remove exhaust camshaft position (CMP) sensor.
  • Ensure timing marks on camshafts aligned as shown [2] & [3] . If not, turn crankshaft 360°.
• Adjust camshafts as follows:
  • Ensure crankshaft at TDC on No.1 cylinder [1] .
  • Slacken bolt of each camshaft sprocket [4] .

    NOTE: Camshaft sprocket bolts have LH thread.

  • Remove camshaft bearing caps [5] .
  • Align camshafts with camshaft alignment tools [6] .
  • Tighten bolt of each camshaft sprocket [4] . Tightening torque: 55 Nm + 90°.
  • Remove camshaft alignment tools [6] .
  • Install camshaft bearing caps [5] .
• Check balancer shaft timing:
  • Ensure crankshaft at TDC on No.1 cylinder [1] .
  • Ensure balancer shaft timing mark aligned with balancer shaft housing timing mark [7] .
• Adjust balancer shafts as follows:
  • Ensure crankshaft at TDC on No.1 cylinder [1] .
  • Slacken bolt of each balancer shaft gear [8] .
  • Rotate balancer shafts until balancer shaft alignment tool can be fitted [9] .
  • Rotate balancer shafts until balancer shaft alignment tool pin can be installed [10] .
  • Tighten bolt of each balancer shaft gear [8] . Tightening torque: 50 Nm + 90°.
  • Remove balancer shaft alignment tool pin [10] .
  • Turn crankshaft in direction of engine rotation to 30° ATDC on No.1 cylinder.
  • Remove balancer shaft alignment tool [9] .