Work on the gas distribution mechanism (Audi Q7-4L-D)

Caution: After installing the camshafts, wait at least 30 minutes before starting the engine to allow the hydraulic lifters to settle. Otherwise, the valves may hit the pistons.

1. The installation details of the timing components are shown in the illustration using the example of the left cylinder head.



2. Processing of valves and their seats, except for lapping, is not permitted.

3. When working with the timing belt, arrange the removed parts so that they can then be installed in their original places.

Removal and installation the old camshafts

4. Remove the timing chain from the camshafts (see Section 29).

5. Make sure that the crankshaft is locked at TDC with locking pin No. 3242 (see illustration 29.24).

6. Make sure the camshafts are at TDC. It should be possible to lock the intake camshaft with the T40060 tool (see paragraph 9 of Section 9), and the groove (In the illustrations) in the exhaust shaft should be located parallel to the joint (A) of the bearing base/cap and slightly above it.





7. Install the T40096 tool onto the intake shaft teeth so that the two arms of the tool engage the two halves of the gear (see illustrations).







The wider lever should fit on the wider half of the gear. Secure the fixture with a knurled nut so that the tooth surfaces align.

8. Install two plastic ties on each camshaft bearing (see illustration), so that the shafts and their bearings can be removed and then installed in their original position.





9. When working on the right cylinder head, remove the T40060 tool from the intake shaft and screw the two sprocket mounting bolts into the threaded holes by 5 turns, as shown in the illustration.



10. When working on the right cylinder head, install the T10172 tool with the T10172/5 adapters on the bolts and turn the shafts approximately 30° counterclockwise so that the groove (A) on the shaft flange is perpendicular to the lower plane of the cylinder head (B) and faces downwards.

Caution: Do not turn the shaft more than specified, otherwise the valves may be damaged.

11. Loosen the bearing bolts in sequence (12-1 in the illustrations) and carefully remove them together with the shafts.

Note: If you intend to reinstall the removed shaft/bearings, do not loosen the clamps or swap the parts afterwards. If necessary, remove the rocker arms with hydraulic lifters.

12. Before installation, make sure that the crankshaft is fixed at TDC with locking pin No. 3242 (see illustration 29.24). and the T40096 device is installed on the intake shaft gear (see paragraph 7).

13. Install the camshafts together with their bearings, holding them by the clamps (see illustration 32.8). In this case, make sure that centering bushings are installed in the holes in the base of bearing No. 4 (see illustrations), which must fit into the holes in the cylinder head.







14. When working on the right cylinder head, follow the steps described in paragraphs 9-10.

15. Make sure the shafts are at TDC (see paragraph 6).

16. Tighten the camshaft bearing bolts in the sequence (1-12 in illustrations 32.11a-b) first by hand, and then with a force of 9 Nm.

17. When working on the right cylinder head, using the T10172 tool with the T10172/5 adapters, turn the shafts approximately 30° clockwise so that the groove (And in the illustration) on the shaft flange was located opposite the hole (B) for the T40060 device.





18. Check again that the shafts are at TDC (see paragraph 6). Remove the T40096 tool and install the timing chain (see Section 29).

Replacing camshafts and their bearings

19. Follow the steps in paragraphs 4-7 and 9-12.

20. Bearing bases and caps are marked on the release side (see illustrations): R - right head bearings, L - left head bearings, 1 - front bearing, 2 - front central, 3 - rear central, 4 - rear.





The markings on the base and lid of a pair must be identical.

21. Install bearing bases No. 1-3 on the cylinder head so that the oil channels (1 in the illustration) in the cylinder head coincided with the oil channels (2) in the bearing bases.





22. Install bearing base No. 4 on the head so that the centering bushings installed in it enter the holes in the cylinder head (see illustration).



23. Make sure that the bearing bases are installed correctly: round side (2 in the illustration) should face the inlet side and the rectangular side (1) should face the outlet side.



24. Make sure the shafts are at TDC(see paragraph), install the bearing caps on the corresponding bases and secure them with clamps (see illustration 32.8).

25. When working on the right cylinder head, follow the steps described in paragraphs 9-10.

26. Follow the steps described in paragraphs 16-18.

Checking hydraulic compensators

27. Checking the hydraulic compensators is carried out in the same way as on the 3.0 TDI engines of the 1st generation (see Section 12).

Replacing valve stem seals

28. To replace the valve stem seals, remove the camshafts and rocker arms with hydraulic compensators (see the relevant subsection above).

29. Set the piston of the corresponding cylinder to BDC and remove the glow plugs (see Chapter 5).

30. Use the tools shown in the illustration to compress the valve spring.



To prevent the valve from falling into the cylinder, supply air to it through the spark plug hole under a pressure of at least 6 bar (if the work is performed without removing the cylinder head).

31. When installing the valve stem seals, use the plastic bushings included in the kit.