M272 (272.982)/84 in W204,W207 — MERCEDES-BENZ

🧭 Before you start

Depressurise the fuel system, remove the intake parts, coils, high-pressure pump, head covers and centrifuge cover. Set the crankshaft position, lock the backlash adjuster, loosen the camshaft gearwheels while counterholding and remove the tensioner and right-bank camshafts. Separate the old chain, join the new one and draw it through, then refit the camshafts, adjusters and new pulse wheels. Fit a new tensioner, apply 70 Nm anti-clockwise to the crankshaft centre bolt, turn the engine and recheck timing before resealing and clearing fault codes.

Fits: platform codes 350, CGI, -T, |

• Timing position: the crankshaft or camshaft is set and locked during this job
• Renewed: timing chain, component note, chain tensioner note

Don't miss

• Cover the chain housing with a cloth and do not drop timing chain pins into the crankcase.
• Renew the chain tensioner, camshaft pulse wheels and high-pressure fuel lines.
• Counterhold the camshafts whenever loosening or tightening the gearwheels.
• Apply 70 Nm anti-clockwise to the crankshaft centre bolt to unlock the new tensioner.
• Sealant bead thickness on the covers is specified at 1.0 mm with a tight tolerance; apply within 10 minutes.
• The centrifuge has a left-hand thread.

Written for this job from the workshop steps below · TorqFix editorial.

🔧 Engine codes this applies to

📋 Procedure

Preparation and removal

1. Timing chain assembly links:
2. Timing chain assembly tool:
3. Always renew the timing chain
4. If the timing chain is to be re-used, mark the running direction before removal
5. Special tool:

6. Note: Avoid bending, torsion or traction
7. Remove the air inlet tube(s)
8. Impact extractor:
9. Injector seal assembly tools:
10. Pull it upwards
11. Note: While storing, protect from damage
12. Fit the timing chain holding tool
13. Remove the ignition coils
14. Remove the ignition leads
15. Fit the special tools
16. Remove the bolts
17. Move aside
18. Note: Do not disconnect the hoses
19. Disconnect the connectors
20. Right cylinder head:
21. Remove the Hall sensors
22. Remove the special tools
23. Use a pry bar at the points shown
24. Note: When removing/fitting the covers, do not damage the fitted sleeves
25. Turn the crankshaft to 55° BTDC for cylinder 1
26. Remove the centrifuge cover
27. Check the position of the camshafts
28. Note: Left-hand thread
29. Turn the crankshaft to 40° ATDC for cylinder 1
30. Correct if necessary
31. Remove the ancillary drive belt
32. Remove the engine lower covers
33. Remove the alternator
34. Remove the chain tensioner
35. Right cylinder head:
36. Lock the camshaft backlash adjuster
37. Note: Use a punch
38. Punch diameter:
39. Loosen the camshaft gearwheel (exhaust)
40. Note: Do not remove
41. When loosening, always use the tool to counterhold
42. From the rear of the cylinder head
43. Torx:
44. Remove the camshaft pulse wheel
45. Check the dowel pin(s) for damage
46. Remove the exhaust camshaft timing adjuster
47. While counterholding the exhaust camshaft
48. Disconnect the right-hand connector from the control unit (viewed from the rear of the engine)
49. Note: Do not disconnect
50. Disconnect the control unit with the wiring and place it on the engine
51. Remove the control unit bracket
52. Disconnect the earth cable from the cylinder head
53. Note: The crankshaft pulley mark will be 305°
54. Check the position of the camshafts
55. Put the open end of the fuel pressure hose into a container
56. Fit the fuel pressure hose to the service valve
57. Reduce the pressure in the fuel system
58. Remove the fuel line between the fuel rail and the fuel distributor
59. Note: Always renew the component
60. Note: If the injectors are separated from the fuel rail, the rail must be renewed
61. Use the special tools
62. Remove the mass airflow meter
63. Remove the high-pressure pump
64. From the rear of the cylinder head
65. Right cylinder head:
66. Loosen the camshaft gearwheel (inlet)
67. Note: Do not remove
68. Remove the cylinder head cover
69. Use a special tool(s) to remove the chain tensioner rail bolt
70. Remove the chain tensioner rail(s)
71. Pull it upwards
72. Remove the camshaft pulse wheel
73. Check the dowel pin(s) for damage
74. Remove the timing chain from the camshaft gearwheel
75. Remove the inlet camshaft timing adjuster
76. Remove the camshaft bearing caps
77. Remove the exhaust camshaft
78. Remove the inlet camshaft
79. Fit the special tools
80. Use the special tools to remove the timing chain pins
81. Note: Cover the timing chain housing with a clean cloth
82. Fit the tool as shown
83. Separate the timing chain
84. Note: Do not drop any timing chain pins into the crankcase
85. Pull the removed timing chain pins out of the chain separating tool

Installation and checks

86. Impact extractor:
87. Timing chain separating tool:
88. Connect the ends of the new chain
89. Until the special tool alignment pins can be removed
90. Remove the special tools
91. Turn the crankshaft to 40° ATDC for cylinder 1
92. Refit the inlet camshaft
93. Refit the camshaft bearing caps
94. Refit the inlet camshaft timing adjuster
95. Lubricate the contact surfaces before assembling
96. Align the locating pins shown
97. Note: Always renew the component
98. Fit the camshaft pulse wheel
99. Note: Always renew the component
100. Note: Finger-tight only
101. Lubricate the contact surfaces before assembling
102. Align the locating pins shown
103. Refit the chain tensioner rail(s)
104. Refit the chain tensioner rail bolt
105. Note: Apply sealant to the bolts
106. Fit the exhaust camshaft
107. Refit the camshaft bearing caps
108. Refit the exhaust camshaft timing adjuster
109. Check the position of the camshafts
110. Fit the camshaft pulse wheel
111. Note: Always renew the component
112. Refit the nuts
113. Tighten the nuts by hand
114. To both camshafts
115. Lubricate the contact surfaces before assembling
116. Refit the cylinder head cover
117. Clean off the old sealant
118. Apply sealant as indicated
119. Within 10 minutes
120. Note: The bead thickness must be 1.0 ± 0.2 mm
121. Tightening sequence:
122. Tighten the inlet camshaft gearwheel
123. Note: The chain tensioner must be removed before the inlet camshaft adjuster can be tightened
124. When tightening, always use the tool to counterhold
125. Renew the chain tensioner
126. Note: Always renew the component
127. Stage 1:
128. Apply a torque of 70 Nm to the crankshaft centre bolt
129. Note: In an anti-clockwise direction
130. While counterholding the exhaust camshaft
131. Left-hand bank:
132. This will unlock the new tensioner
133. Remove the counterhold tool
134. Turn the crankshaft 90° in the direction of rotation
135. Note: This will tension the new hydraulic tensioner
136. Turn the crankshaft to 40° ATDC for cylinder 1
137. Check the position of the camshafts
138. Remove the punch used to lock the camshaft backlash adjuster
139. Tighten the exhaust camshaft gearwheel
140. When tightening, always use the tool to counterhold
141. Refit the cylinder head front cover
142. Note: When removing/fitting the covers, do not damage the fitted sleeves
143. Note: The bead thickness must be 1.0 ± 0.5 mm
144. Apply sealant as indicated
145. Reconnect the fuel distributor bracket to the cylinder head cover
146. Note: Do not tighten the fuel lines until all the attached components are securely fitted
147. Stage 1:
148. Refit the centrifuge
149. Note: Left-hand thread
150. Stage 1:

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