Timing chain replacement: Mercedes-Benz 646.9 84, 85, 86, 89, 90 W906 2.1 CDI (646.984, 646.985, 646.986, 646.989)

🧭 Before you start

Fits: platform codes 209, CDI, |, 211, 213, 215, 309, 311, -4MATIC, 313, 315, 411, 413, 415, 509, 511, 515

• Timing position: the crankshaft or camshaft is set and locked during this job
• Renewed: gaskets

Don't miss

• If the timing chain is to be re-used, mark the running direction before removal

🔧 Engine codes this applies to

📐 24 workshop diagrams for 646.984

Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.

📋 Procedure

Preparation and removal

1. Always use new gaskets
2. If the timing chain is to be re-used, mark the running direction before removal
3. Remove the air filter housing and hoses
4. Use a timing chain assembly link
5. Remove the injection lines

6. Remove the fuel return hoses from the injectors
7. Disconnect the injector wiring
8. Disconnect the camshaft position sensor
9. Disconnect the remaining wiring and hoses from the cylinder head
10. Remove the cylinder head cover
11. Remove the coolant expansion tank and place it aside
12. Note: Do not disconnect
13. Disconnect the chain
14. Unbolt the dipstick tube bracket
15. Note: Move it aside
16. Remove the chain tensioner
17. Fit the timing chain holding tool
18. Separate the timing chain
19. Use the special tools to remove the timing chain pins

Installation and checks

20. Extractor:
21. Connect the old chain to the new one
22. Note: Renew the sealing ring
23. Connect the ends of the new chain
24. Secure the chain
25. Use the special tool
26. Tighten the special tool
27. Check for correct fitting
28. Remove the timing chain holding tool
29. Refit the chain tensioner
30. Note: Renew the sealing ring
31. Turn the crankshaft to TDC for cylinder 1
32. Check the camshaft timing marks
33. Remove the special tools
34. Pull the removed timing chain pins out of the chain separating tool
35. Lock the inlet camshaft gearwheel
36. Use the locking pins
37. If the marks are misaligned
38. Remove the camshafts
39. Fit the camshafts
40. Check the timing marks again
41. Remove the camshaft locking pins
42. Refit all parts in the reverse order of removal

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