Timing Belt — Removal and Installation (Audi A6 C5)

Removal

1. Remove the accessory drive V-belt (see the relevant chapter).

2. Remove the cap from the oil filler neck.

3. Turn the crankshaft in the direction of engine rotation by the central bolt securing the drive gear until the inscription "OT" appears in the hole of the oil filler neck (top dead center) on the camshaft (see illustration).



4. Unscrew the threaded plug on the cylinder block at approximately the level of the middle cylinder.

5. Screw in the locking pin, catalog number 3242, instead of the plug (see illustration). Make sure that the pin enters the hole in the crankshaft cheek and locks the shaft.





6. Unscrew the coolant expansion tank mounting bolts (see arrows 1 in the illustration).



7. Disconnect the coolant level sensor plug at the bottom of the expansion tank and move the tank away from the work area without disconnecting the hoses 2 from it (see illustration 2.6).

8. Unscrew the bolts 1 securing the vacuum pump and turn the pump on the end face of the left cylinder head to the left (see arrow in illustration).



9. Remove the vacuum pump by pushing it backwards without disconnecting the low pressure hoses from it.



10. Disconnect plug 1 of the mass air flow sensor, then loosen clamp 2 securing the supply air duct to the air filter housing (see illustration).



11. Disconnect hose 3, unscrew bolt 4 and remove the air filter (see illustration 2.10).

12. Unscrew the fastening nut, remove the fuel filter from the bracket and move it away from the work area without disconnecting the fuel lines from it.

13. Unscrew the mounting bolts (see arrows in the illustration) and remove the air duct connecting the turbocharger and intercooler on the right cylinder head.





14. Remove the covers that cover the ends of the camshafts by prying the covers with a screwdriver (see arrow in illustration).

Attention! The covers are damaged when removed, so they must be replaced after each dismantling. Proceed carefully so as not to damage the seating surface of the cover on the cylinder head.

15. Insert the locking plates, catalog number 3458, into the grooves on the ends of the camshafts of both cylinder heads and attach chains to them to prevent the plates from falling out (see illustration). If there are no such stoppers, then use suitable rulers 40 mm wide and 5 mm thick or make the plates yourself.

Caution! The said locking plates must not be used as a stop to prevent the shafts from turning when unscrewing the camshaft gear mounting bolts.

16. Unscrew bolts 1 and remove the vibration damper from the fuel injection pump gear (see illustrations 2.16 and 2.16a).

Caution! Do not unscrew nut 2 (see illustration 2.16), as this may lead to a violation of the basic adjustment of the fuel injection pump. Subsequent adjustment of the fuel injection pump is impossible even in a workshop.

17. Mark the direction of the fuel injection pump drive toothed belt with chalk, marker or paint if it is to be reinstalled. Failure to maintain the previous direction of the toothed belt during its further use will result in its damage or breakage.

18. Loosen the tension of the fuel injection pump drive toothed belt by turning the roller with a socket wrench and remove the fuel injection pump drive toothed belt from the camshaft gear (see illustration).



19. Unscrew the eight bolts 1 and remove the accessory drive belt pulley from the crankshaft. The central bolt 2 secures the timing gear to the crankshaft, so there is no need to unscrew the central bolt when removing the belt pulley (see illustration).





20. Remove the lower part 4 of the timing gear protective cover (see illustration).



21. Unscrew bolts 1, 2 and 3 and remove the viscous coupling fan mounting bracket (see illustration 2.20). The guide rollers are also located on this bracket.

22. Unscrew the three bolts (see arrows in the illustration) and remove gear 1, from which the high-pressure fuel pump is driven by a toothed belt.





23. Loosen the bolts securing the camshaft gears to their hubs, holding the gears from turning with a special tool, catalog number 3036 (see illustration).

Attention! It is not necessary to completely unscrew the camshaft gear mounting bolts.

24. Slowly turn the timing belt tension roller with an 8 mm socket wrench to the right (see arrow in illustration) so that the tensioner plunger enters the housing and the holes in the housing and plunger are aligned. Insert a suitable pin, for example, a pin with catalog number T40011, into the aligned holes, thereby fixing the plunger in the tensioner housing.

Caution! The timing belt tensioner has an oil-filled plunger and therefore the plunger should be pressed into the tensioner housing slowly with a uniform force. Excessive force may damage the tension roller.

25. Remove the gear together with the toothed belt from the hub of the left cylinder head camshaft using a suitable two-jaw puller, for example, the T40001 puller, resting its bolt against the central bolt of the hub fastening (see illustration).



26. Remove the timing belt from the gears and guide rollers.

Installation and adjustment

27. Place the toothed belt on the crankshaft gear, then on the camshaft gear of the right cylinder head, the tension and guide rollers and the water pump.

28. Place the toothed belt on the removed camshaft gear of the left cylinder head, then put the gear together with the belt on the shaft hub and screw in the gear mounting bolts (see illustration).

Attention! The final tightening of the bolts securing the camshaft gears to the hubs should not be performed at this stage. They should be tightened so that the gears can be turned, but they should not move axially on the hubs.

29. Turn the tension roller to the right using an 8 mm socket wrench (see arrow in illustration) so that it was possible to remove the T40011 pin, which secured the tensioner plunger.



30. Tighten the toothed belt by turning the tension roller eccentric with a torque wrench applying a force of 15 Nm counterclockwise and in this position of the eccentric tighten the roller mounting bolt (see illustration).



31. Perform the final tightening of the camshaft gear mounting bolts, holding them from turning with the tool, catalog number 3036 (see illustration).



32. Install in place and secure with bolts 1-4 (see illustration 2.20) fan mounting bracket with viscous coupling. Tightening torques: bolt 1-45 Nm, bolt 2-10 Nm, bolt 3-22 Nm, bolt 4-10 Nm.

33. Lock the fuel injection pump gear with a thrust roller, catalog number 3359, by inserting it into the hole on the gear and the corresponding hole on the cylinder block (see illustration). If there is no such thrust roller, then use a punch of suitable diameter and length.



34. Install gear 1 of the fuel injection pump drive toothed belt on the camshaft of the left cylinder head and secure it with three bolts (see arrows in the illustration). Do not perform final tightening of the bolts at this stage.



35. Turn the gear on the camshaft so that its mounting bolts are located in the center of their longitudinal holes.

36. Install the fuel injection pump drive toothed belt. If the previous belt was installed, observe its direction of travel.

37. Turn the injection pump toothed belt tension roller counterclockwise until the arrows 1 are aligned. In this position of the roller, tighten its mounting bolt with an end insert, catalog number 3078 (see illustration).



38. Remove the locking devices that were used to lock the camshafts, the fuel injection pump drive gear and remove the locking pin 3242 that was used to lock the crankshaft (see illustration).



39. Turn the crankshaft in the direction of engine rotation and set the cylinder piston to TDC. Lock the crankshaft again by inserting the locking pin 3242 into the corresponding hole on the cylinder block (see illustration 2.38).

40. Make sure that the camshafts can be locked using the 3458 stoppers (see illustration). Otherwise, repeat the timing belt tension adjustment.



41. Remove all locking devices used to lock the camshafts and crankshafts.

42. Make sure that the tension of the fuel injection pump drive toothed belt corresponds to the required one: arrows 1 and 2 of the tension roller must be aligned (see illustration).



43. Install the vibration damper and the gears of the fuel injection pump drive toothed belt.

44. Install the V-belt pulley. The pulley locking tab should be positioned as shown in the illustration (see arrow).



45. Screw the plug into the hole on the cylinder block, into which the locking pin was installed to fix the crankshaft, after replacing the plug sealing ring with a new one. The tightening torque of the plug is 10 Nm.

46. Install the vacuum pump on the left cylinder head.

47. Install the camshaft covers (see arrow in illustration) on the right and left cylinder heads.



Next, the installation of the dismantled components is carried out in the reverse order of removal.

(A link to the original source is available on the website audimanual.ru)