General information
1. The main purpose of the belt is to drive the camshaft (ov). If, while the engine is running, the belt breaks or jumps off, the gas distribution is disturbed, the pistons hit the valves - there will be a serious breakdown. Therefore, it is very important for the belt to be properly tensioned. Check the condition of the timing belt regularly.
Withdrawal
2. Disconnect the battery by disconnecting its negative cable (see chapter 5A).
3. Apply the handbrake, raise the front of the vehicle and install safety stands. If necessary, remove the lower protective casing of the power unit.
4. Access to the belt is possible after detaching the front panel of the body (with hood latch). Move the panel away from the body as far as possible without disconnecting the wiring and radiator hoses. To do this, first remove the front bumper as described in chapter 11. Disconnect the three quick-release fasteners of the soundproofing panel, unscrew the bolts securing the air duct to the hood lock bracket and the air filter. Remove the power steering oil cooler from the bottom of the cooling system radiator. On the left side of the radiator, disconnect the wiring braid from the mounts. Unscrew the bolts securing the hood lock bracket assembly at the bottom of the body, unscrew the upper bolts that are behind the headlights. With the help of a second person, remove the entire front panel assembly and move it away from the vehicle as far as possible. To hold the panel, Audi mechanics usually use special template brackets, however, it is possible to make them from a bar without cutting the threads on its ends. Wrap these devices in the body side members (pic. 4.4, a-g).
5. Remove the accessory drive belts as described in paragraph 6. Remove the tensioner from the front of the engine using a hex wrench (pic. 4.5, a, b).
6. Remove the viscous fan coupling as described in paragraph 5 of chapter 3. It is removed using a hexagon from behind, holding it still from behind with a bolt inserted abutting against the cylinder block (pic. 4.6.a, b).
7. Loosen and remove the upper outer timing belt cover (pic. 4.7, a, 6).
8. If the timing belt needs to be installed back, mark the direction of rotation on its back with a marker.
9. Set the engine to TDC as described in paragraph 2. Application: Make sure that ALL TDC marks match exactly, since the mark on the camshaft sprocket alone cannot give accuracy when installing the belt. If the mark on the camshaft sprocket is slightly out of alignment, apply a temporary second mark to use during installation.
10. Holding the crankshaft motionless by the center pulley bolt with a wrench, unscrew the pulley mounting bolts (or anti-vibration damper) to the crankshaft sprocket. Remove pulley or damper (pic. 4.10, a, b).
11. Remove the bolts and remove the lower outer timing belt cover from the cylinder block (pic. 4.11).
Engines ADP, ADR (until 07/97). AFY (until 07/97), AEB, AJL, APT, APW
12. Using a Torx socket, loosen the bolt securing the tensioner roller hub to the tensioner arm. Push the tensioner hub clockwise to loosen the timing belt (pic. 4.12).
ADR engines (from 08/97) and AFY (from 08/97)
13. Insert a hexagon into the hole in the tensioner hub and slowly turn the tensioner counterclockwise, overcoming the resistance of the spring. Line up the small holes at the top of the tensioner and the inner cylinder, insert a 2.0mm drill tail to lock the tensioner in position (pic. 4.13). DO NOT loosen any of the tensioner bolts.
AHL engines
14. Unscrew the central nut of the semi-automatic tensioner so that the belt is completely relieved of tension.
All engines
15. Pull the timing belt off all sprockets and remove the belt from the engine (pic. 4.15). If you have to install the belt back. DO NOT BEND it too much.
Examination
16. Check the timing belt carefully for wear, delamination, cracks and decomposition of its material from the ripe oil. If traces of oil on the belt are found, find the cause and eliminate it, wash off all traces of oil around the belt installation site. If there is even the slightest doubt about the suitability of the belt, its replacement will be much cheaper than a potential engine repair. If the engine is overhauled, or has traveled more than 60,000 km since the last belt change, the belt must be replaced out of all circumstances.
Note: If the belt is removed for a long time. hang a warning label on the steering wheel to prevent the engine from starting or turning over unintentionally.
Installation
Zzigetali ADP. ADR (until 07/97), AFY (until 07/97), AEB, AJL, APT, APW
17. Make sure that the TDC mark on the camshaft sprocket matches the corresponding mark on the valve cover, as described in paragraph 2.
18. Temporarily install the lower timing belt cover, install the pulley on the crankshaft sprocket, securing with two mounting screws - note that the asymmetrical holes allow the pulley to be installed in only one position.
Note: The pulley bolts are long threaded - no need to tighten them all the way.
Make sure the marks match and remove the pulley and timing belt cover.
19. Circle the belt under the crankshaft sprocket. If the old belt is installed, pay attention to the pre-applied mark of the direction of its rotation.
20. On ADP engines, temporarily install a pulley not a crankshaft sprocket and check the coincidence of the marks on the crankshaft pulley and the auxiliary shaft sprocket. The mark on the crankshaft pulley should align with the dot on the auxiliary shaft sprocket. Note that the OT mark on the auxiliary shaft sprocket is irrelevant. Check the position of the distributor slider - it should look towards the contact in the cover intended for the first cylinder. After checking the marks, remove the pulley.
21. Align the teeth of the belt with the teeth of the crankshaft sprocket, lay it on the auxiliary shaft sprocket and camshaft sprocket (pic. 44.21). Pay attention to the belt rotation direction mark.
22. Lay the back of the belt around the tensioner pulley - do not bend the belt excessively. Select the front slack of the belt - the slack must be left on the side of the tensioner pulley.
23. Tension the belt by turning the tensioner hub counterclockwise and the spring-loaded lever clockwise; for this purpose, a hole and a protrusion are intended. Instead of the specially provided VAG tool, you can use hook-nose pliers. Rotate the tensioner until the spring-loaded inner piston is fully extended so that the outer piston protrudes about 1.0 mm, then tighten the fixing bolt. Check that the prong "A" aligned with the top end of the outer piston (pic. 4.23, a, b). If necessary, loosen the fixing bolt and re-adjust the tension. The distance between the top of the outer piston and the top of the eye of the inner piston should be 25.0...29.0 mm.
Application: After installing a new timing belt, the eccentric hub will eventually (with belt stretch) unfold. bringing the top of the outer piston into position "IN". If the outer piston is in position C, then the tensioner or belt has wear limit.
24. On ADP engines, temporarily install the crankshaft pulley and check that the marks on the auxiliary shaft match the mark on the pulley. Remove the pulley.
ADR engines (from 08/97) and AFY (from 08/97)
25. Make sure that the mark on the camshaft sprocket is correctly aligned with the corresponding mark on the inner timing belt cover, as described in paragraph 2. Circle the belt under the crankshaft sprocket, paying attention to the pre-marked direction of rotation of the belt if you are installing the old belt.
26. Temporarily put on the lower timing belt cover and crankshaft pulley, securing it with a pair of bolts (asymmetric holes allow the pulley to be placed in only one position).
27. Check up alignment of marks on a pulley and a cover. Since the auxiliary shaft does not drive anything other than the oil pump, its position does not matter.
28. Align the teeth of the belt with the crankshaft sprocket, lay it around the auxiliary shaft and camshaft sprockets. Observe the correct direction of rotation of the belt - use the pre-applied mark for this.
29. Lay the belt with the back side on the tensioner roller. Do not bend the belt too much. The front shoulder of the belt should be tight - the slack should be on the side of the tensioner 30. With an 8.0 mm hex, turn the tensioner roller counterclockwise, remove the drill and release the roller so that the belt is taut.
AHL engines
31. Make sure that the mark on the crankshaft sprocket is aligned with the mark on the inner timing belt cover - see paragraph 2.
32. Circle the belt around the camshaft sprocket, observing the correct direction of its rotation if the old belt is installed.
33. Temporarily put on the lower timing belt cover and fasten the crankshaft pulley to the sprocket with a couple of bolts, paying attention that the asymmetrical holes allow the pulley to be installed in only one position.
34. Check up alignment of marks on a pulley and a cover.
35. Align the teeth of the belt with the crankshaft sprocket, lay it around the water pump and camshaft sprockets. Observe the marks for the direction of rotation of the belt.
36. Lay the belt with the back side around the tensioner roller - do not bend the belt too much. The front shoulder of the belt must be taut - the slack must be on the side of the tensioner pulley. The tab at the base of the tensioner should align with the mark on the cylinder head.
37. Audi mechanics use a specialized tool that fits into two holes on the tensioner pulley. Instead, you can take right-angled needle nose pliers. Turn the tensioner counterclockwise as far as it will go, then turn it slowly clockwise until the pointer is 10.0mm below the lug. Continue to rotate the tensioner until the two pointers are opposite each other and in this position tighten the nut to the prescribed torque (pic. 4.37).
All engines
38. Taking the central bolt of the crankshaft sprocket with a key or a head with a knob, turn the crankshaft two full turns. Set the piston of the first cylinder to TDC of the compression stroke - see paragraph 2 and make sure that the marks on the crankshaft pulley, auxiliary and camshaft sprockets are correctly aligned. Check timing belt tension and correct if necessary.
39. Install the lower part of the outer timing belt cover, install the crankshaft pulley. Tighten the pulley mounting bolts to the prescribed torque.
40. Install the upper part of the outer timing belt cover.
41. Install the viscous fan clutch as described in chapter 3, install the accessory drive belt tensioner and tighten the bolts. Install accessory belts - see paragraph 6.
42. Install the hood lock bracket assembly in the reverse order of removal.
43. Establish the lower protective casing of the power unit and lower the car.
44. Connect the battery as described in chapter 5A.
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