Withdrawal
1. The primary function of the timing belt is to drive the camshaft, but it is also used to drive the water pump. The fuel pump is driven from the rear end of the camshaft by an additional drive belt. If the belt breaks or slips, the timing will be off. Doing so can cause the valves to hit the pistons, causing serious damage.
2. For this reason, it is important to regularly inspect the timing belt for signs of wear and contamination and check its tension.
3. Removing the inner toothed belt cover is described as part of the cylinder head removal procedure (see chapter 11).
4. Before starting work, disconnect the negative cable from the battery.
5. Apply the handbrake, then jack up the front of the vehicle and place it on axle stands. Remove the lower shield of the engine compartment and remove it from under the car.
6. Remove the front bumper as described in Section 11.
7. Remove both headlights as described in Section 12 (see illustration).
8. Disconnect the cable from the hood lock, then unscrew the bolts of the cross member from the side panels of the engine compartment and the front brackets and remove it. Also remove the small air duct located on the radiator (see illustration).
9. Turn off bolts of the top fastening of a radiator and remove brackets (see section 2). Do not disconnect hoses from the radiator.
10. The radiator must now be separated from the supports on the right side and brought forward to create a working space in front of the engine. To do this, unscrew the bolts of the brackets on the right side of the radiator, on the 3D engine, remove the air ducts, then unscrew the bottom mounting nuts and bring the right side of the radiator forward. There is a special Audi bracket designed to hold the radiator away from the engine, but a metal strip or block of wood is a suitable replacement (see illustrations). Alternatively, you can remove the radiator (see section 2), which will create a much larger workspace.
11. Remove the auxiliary drive belt as described in Chapter 7 (see illustrations).
12. Remove thermoviscous fan assembly (see section 2). To do this, first unscrew the impeller fastening bolts, then block the flange/pulley and unscrew the thermoviscous coupling fastening nut. Homemade blocking tool can be made from a metal strip and two bolts (the distance between the centers of the holes on the flange/pulley is approx. 18 mm) (see illustrations).
13. Loosen the bolts and remove the upper drive belt cover, tensioner and spring mount, then remove the assembly (see illustrations).
14. Remove the camshaft cover as described in Chapter 8.
15. Remove the bolts securing the cover to the rear of the engine to gain access to the fuel pump drive belt.
16. Release spring clips and remove the top cover of a gear drive belt. Loosen the bolts and remove the lower toothed belt cover (see illustrations).
17. Turn the crankshaft and set the engine to TDC as described in Chapter 2. This procedure involves removing the fuel pump drive belt and installing the camshaft lock rod. The TDC marks on the flywheel and on the high pressure fuel pump must be aligned. The alignment marks on the base of the crankshaft pulley and the inner cover must also match (see illustration).
18. Block the crankshaft and loosen the central bolt of the vibration damper. There is a special Audi tool installed inside the vibration damper, but on manual transmission models, it is enough to select 4th gear and have an assistant depress the brake pedal. On automatic transmission models, remove the torque converter housing cover bolts and have an assistant insert a wide screwdriver between the teeth of the flywheel crown. On models with a manual transmission, remove the starter and insert a screwdriver between the teeth of the flywheel crown or screw a suitable bolt into one of its holes. Remove vibration damper center bolt (see illustrations). Please note that this bolt should be changed after each removal.
19. Loosen and remove the bolts securing the vibration damper to the crankshaft sprocket, which should still be locked (see illustration).
20. Remove the vibration damper from the sprocket, see illustration). If the sprocket moves with the vibration damper, screw in the two bolts a few turns of thread and tap them gently to hold the sprocket in position.
21. Remove the bolts securing the lower drive belt cover to the cylinder block.
22. Loosen the bolt on the toothed belt tensioner, then turn the gear clockwise to reduce belt tension and tighten the bolt.
23. Mark the drive belt with an arrow indicating the direction of rotation.
Note: If the toothed drive belt cannot be replaced, it must be oriented during installation so that it rotates in the same direction. Do not bend the toothed belt as this may damage it.
24. Remove the toothed drive belt from the sprockets of the crankshaft, camshaft and water pump (see illustration).
Inspection
25. If the belt is contaminated with coolant or grease, find the source and eliminate the cause. Inspect the belt for damage and signs of wear, especially around the leading edges of its teeth. Replace the belt if there is any doubt about its condition; the cost of replacing the belt is negligible compared to the cost of repairing the engine, which would be required if the belt burst on the move. The belt must also be replaced if the vehicle has traveled the distance specified by the belt manufacturers since it was installed.
Note: If the toothed drive belt is not installed immediately, it is recommended that a warning note be attached to the steering wheel to prevent accidental starting of the engine.
Installation
26. Make sure the crankshaft and camshaft are still at TDC (see chapter 2).
27. Referring to Chapter 6, loosen the camshaft sprocket bolt half a turn. Gently tap the sprocket off the camshaft taper by carefully inserting a soft metal drift through the hole in the inner timing belt cover.
28. Route the timing belt loosely over the crankshaft sprocket (see illustration).
Warning: Orient the belt according to the direction of rotation marks made before removing it.
29. Install the belt on the crankshaft sprocket, then install it on the water pump and camshaft sprockets (see illustration). Make sure that the teeth of the belt are in the grooves on the sprockets.
30. Pass the belt with the flat side over the idler roller and tensioner roller. Do not bend or twist the belt while installing it.
31. Make sure that the left run of the belt is taut, that is, all the slack should be in the part of the belt that passes over the tensioner roller.
32. Tension the toothed belt by turning the tensioner counterclockwise. The tensioner hub has two holes; install two drills in them, insert a suitable lever between them and turn the mechanism. With the correct tension in the middle of the run between the camshaft and water pump sprockets, the belt can only be twisted by fingers by 90°. Tighten the bolt with a torque specified specifications.
33. The tensioner hub has two holes; install two drills in them, insert a suitable lever between them and turn the mechanism. With the correct tension in the middle of the run between the camshaft and water pump sprockets, the belt can only be twisted by fingers by 90°. Tighten the bolt with the tightening force specified in the Specifications.
34. Tighten the camshaft sprocket bolt with a torque specified specifications (see chapter 6), being careful not to bend the blocking rod (see illustration).
35. Remove the camshaft blocking rod.
36. Turn the crankshaft two full turns, then make sure that the TDC alignment marks are aligned (see chapter 2). Check that the locking pin can still be inserted into the camshaft groove and check the toothed belt tension.
37. Establish the bottom cover of a driving belt on the block of cylinders and clamp its bolts.
38. Lubricate the threads and bottom surface of the crankshaft sprocket center bolt head.
39. Install the vibration damper on the sprocket, then insert the sprocket bolts into it and install the new center bolt and washer. Block the crankshaft in the same way as when removing the vibration damper, then tighten the bolts with a tightening torque regulated specifications (see illustrations).
40. Tighten the central bolt of the sprocket with the tightening torque specified specifications (see illustration).
41. Install the fuel pump drive belt (see chapters 2 And 5), then install the belt cover and tighten the bolts.
42. Install the bottom cover of the toothed belt, then install its top cover and attach it with spring clips (see illustrations).
43. Install the camshaft cover, see Chapter 8.
44. Install the auxiliary drive belt tensioner, then install the belt itself (see chapter 7).
45. Install the fan assembly as described in Section 2.
46. Install the radiator, brackets and air ducts and tighten the bolts.
47. Establish a cross member and the lock of a cowl and tighten bolts.
48. Install the headlights as described in Section 12.
49. Install the front bumper (Section 11).
50. Install the undershield of the engine compartment and lower the vehicle to the ground.
51. Connect the negative cable to the battery.
52. If the radiator has been removed, replenish the cooling system.
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