TorqFix

Astra G Z12XE — OPEL / VAUXHALL

Astra G Z12XE on Opel / Vauxhall: 212 steps, engines Z12XE. What to remove, in what order, and what to check after.

Timing chain renewal on the Astra G 1.2 16V with the Z12XE engine. It is one of the longer chain jobs: the oil and coolant are drained, the sump, oil filter, oxygen sensor and catalytic converter come off, and the alternator, air-conditioning compressor (left connected), thermostat housing, coolant pump, ignition module and wiring loom are cleared. The engine is held on a support while the right-hand engine support and bracket are removed. Camshaft alignment and adjustment tools lock the timing at TDC for cylinder 1, the chain tensioner is locked with a pin and the old chain and rails come out. Check the special tools fit after 2 crankshaft rotations before the cover is sealed.

212 steps 1 engine code

🧭 Before you start

Drain oil and coolant, remove the sump, catalytic converter, ancillary belt and tensioner, alternator, coolant pump and ignition module, and support the engine to remove the right-hand mounting. Set TDC for cylinder 1, fit the camshaft alignment tools, lock the tensioner, remove the cover, rails and chain. Fit the new chain and rails, release the tensioner slowly, turn the engine 2 rotations, confirm the tools fit, then seal and rebuild.

Fits: platform codes 1.2, 16V

  • Opens: coolant, engine oil
  • Timing position: the crankshaft or camshaft is set and locked during this job
  • Special tools named: locking pin
  • Renewed: bolt, seal exhaust

Don't miss

  • Always renew the timing chain.
  • Lock the chain tensioner with a locking pin before removal, and release it slowly on refit.
  • Mark the ancillary belt's direction of rotation and refit it running the same way.
  • Turn the crankshaft two rotations by hand and confirm the special tools still fit.
  • Renew the bolt where indicated, and apply sealant to the timing cover and sump.

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

🔧 Engine codes this applies to

Z12XE

📐 69 workshop diagrams for Z12XE

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

Astra G Z12XE — Z12XE · diagram 1
Astra G Z12XE — Z12XE · diagram 2
Astra G Z12XE — Z12XE · diagram 3
Astra G Z12XE — Z12XE · diagram 4
Astra G Z12XE — Z12XE · diagram 5
Astra G Z12XE — Z12XE · diagram 6
Astra G Z12XE — Z12XE · diagram 7
Astra G Z12XE — Z12XE · diagram 8
+ 61 more diagrams
🔒 69 workshop diagrams for this job Ask about your Opel / Vauxhall Z12XE — free or sign up free to see the drawings

📋 Procedure

Preparation and removal

  1. Engine support:
  2. Crankshaft front radial seal fitting tool:
  3. Always renew the timing chain
  4. Drain the engine oil
  5. Remove the oil sump
Z12XE? Steps differ between engine variants — check this job against your exact car before you commit to it. Check my car — free →
  1. Remove the lifting eyes
  2. Remove the oxygen sensor
  3. Remove the oil filter
  4. Remove the oil filter cartridge
  5. Remove the mass airflow meter
  6. Remove the air filter housing
  7. Remove the engine support
  8. Remove the engine support bracket
  9. Vehicles without air conditioning:
  10. Turn the tensioner pulley clockwise until the locking pin fits
  11. Remove the ancillary drive belt
  12. Note: At removal, mark the direction of rotation; when refitting ensure the drive belt rotates in the same direction
  13. Vehicles with air conditioning:
  14. Turn the tensioner pulley clockwise to its stop
  15. Note: A click will be heard when the tensioner locks
  16. Remove the ancillary drive belt
  17. Note: At removal, mark the direction of rotation; when refitting ensure the drive belt rotates in the same direction
  18. Remove the engine support
  19. Vehicles without air conditioning:
  20. Remove the tensioner spring attaching bolts
  21. Remove the ancillary drive belt tensioner
  22. Vehicles with air conditioning:
  23. Release the tensioner
  24. Turn the tensioner anti-clockwise to release the tension
  25. Remove the tensioner spring attaching bolts
  26. Remove the ancillary drive belt tensioner
  27. All vehicles:
  28. Remove the alternator
  29. Remove the expansion tank pressure cap
  30. Drain the coolant
  31. Remove the thermostat housing
  32. Remove the upper radiator hose
  33. Disconnect the coolant hoses
  34. Disconnect the camshaft position sensor(s)
  35. Disconnect the oil pressure switch
  36. Remove the coolant temperature sensor
  37. Remove the wiring loom from the cylinder head
  38. Remove the coolant pump pulley
  39. Remove the coolant pump
  40. Vehicles with air conditioning:
  41. Unbolt the air-conditioning compressor
  42. Remove the air-conditioning compressor but do not disconnect
  43. All vehicles:
  44. Disconnect the positive crankcase ventilation hose
  45. Disconnect the ignition module connector
  46. Remove the ignition coil cover
  47. Remove the ignition module
  48. Turn the crankshaft to 10° BTDC for cylinder 1
  49. Check the crankshaft timing marks
  50. Note: Do not remove
  51. Use the special tool to counterhold
  52. Remove the access plug
  53. Turn the crankshaft to TDC for cylinder 1
  54. Check the position of the camshafts
  55. Check that the special tools fit
  56. Remove the crankshaft hub
  57. Use the special tool
  58. Remove the timing chain cover
  59. Lock the chain tensioner with a locking pin
  60. Remove the timing chain upper guide rail
  61. Remove the chain guide rail
  62. Remove the chain tensioner rail(s)

Installation and checks

  1. Fit the coolant pump
  2. Camshaft alignment tool:
  3. Adjustment tool:
  4. Note: Apply sealant before fitting
  5. Refit the chain guide rail
  6. Tighten the timing cover bolt(s)
  7. Remove the special tools
  8. Refit the crankshaft hub
  9. Align the drive unit with the front axle body
  10. Renew the bolt and tighten
  11. Refit the crankshaft pulley
  12. Turn the crankshaft two rotations by hand
  13. Turn the crankshaft to 10° BTDC for cylinder 1
  14. Remove the access plug
  15. Turn the crankshaft to TDC for cylinder 1
  16. Check the position of the camshafts
  17. Check that the special tool fits
  18. Refit the access plug
  19. Reconnect the connector
  20. Reconnect the positive crankcase ventilation hose
  21. Vehicles with air conditioning:
  22. Refit the air-conditioning compressor
  23. All vehicles:
  24. Refit the coolant pump pulley
  25. Refit the coolant temperature sensor
  26. Reconnect the oil pressure switch
  27. Reconnect the camshaft position sensor(s)
  28. Refit the wiring loom to the cylinder head
  29. Reconnect the coolant hoses
  30. Refit the upper radiator hose
  31. Refit the engine support
  32. Engine support (bolts):
  33. Note: Release the tensioner slowly
  34. Refit the engine support bracket
  35. Refit the engine support
  36. Remove the engine support tool
  37. Refit the front right splash guard
  38. Refit the air filter housing
  39. Refit the mass airflow meter
  40. Refit the air inlet hose
  41. Refit the oil filter cartridge
  42. Renew the gasket
  43. Replace the oil filter(s)
  44. Refit the exhaust manifold heat shield
  45. Refit the oxygen sensor
  46. Use the special tool
  47. Attach the lifting eyes to the cylinder head
  48. Refit the oil sump
  49. Oxygen sensor
  50. Refit the oil drain plug
  51. Renew the seal
  52. Exhaust:
  53. Refit the catalytic converter
  54. Refit the catalytic converter mounting bracket
  55. Reconnect the oxygen sensor
  56. Reconnect the battery earth cable
  57. Refill the engine oil
  58. Refill the cooling system
Workshop diagrams

Ask TorqFix about your Opel / Vauxhall Z12XE — it answers with the exact sequence for that engine and the workshop drawing for each step. First question is free after a 20-second sign-up, no card.

Ask about your Opel / Vauxhall Z12XE — free → or sign up free to see the drawings

Other OPEL / VAUXHALL procedures

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TorqFix was built by a mechanic — after a 2,700 km drive with five roadside repairs that no diagnostic tool could explain.

The figures on this page come from manufacturer workshop documentation and are shown as they are. The page is assembled automatically from that data — it is not written by an AI. The AI works in the chat, where it answers for your specific car. It writes nothing here.

Variants of the same model differ. Cross-check torque against the factory manual for your engine before final tightening.

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Workshop data on this page last updated 20 Sep 2026.