Repair and service Audi A8 in body D2 with 1994 for 1999 of release.
1. Car operation
2. Maintenance service
3. Petrol engines of 2,8 l
3.1. The general data
3.2. Removal and engine installation
3.3. A poliklinovoj belt
3.4. Гаситель fluctuations
3.5. Replacement of a gear belt
3.6. A two-mass flywheel
3.7. A frictional overlay
3.8. The gauge of frequency of rotation of the engine
3.9. A cranked shaft
3.10. Pistons and rods
3.11. An inlet collector
3.12. The left cover of a head of the block of cylinders
3.13. The right cover of a head of the block of cylinders
3.14. A head of the block of cylinders
3.15. A camshaft
3.16. Check of hydraulic pushers of valves
4. Petrol engines of 3,7 and 4,2 l
5. Diesel engines of 2,5 l
6. Diesel engines of 3,3 l
7. Systems of ignition and injection of fuel of petrol engines
8. System of release of the fulfilled gases of cars with petrol engines
9. The power supply system of diesel engines
10. System of prestarting heating of diesel engines
11. System of release of the fulfilled gases of cars with diesel engines
12. Greasing system
13. Cooling system
14. Coupling
15. A transmission
16. Shaft of a drive of forward wheels
17. Features of a design of transmission of all-wheel drive cars
18. A suspension bracket
19. Wheels and tyres
20. A steering
21. Brake system
22. A body
23. Heating and air-conditioning system
24. An electric equipment
25. Electric schemes


3.16. Check of hydraulic pushers of valves

Correct installation клапанных backlashes in many respects defines engine work. If клапанные backlashes too big, raises шумность and the engine overall performance as valves open too late decreases and are closed too early. If клапанные backlashes too small, valves cannot be closed completely on the hot engine that can lead to its serious damage.
On engines establish hydraulic pushers which automatically under the influence of pressure in greasing system compensate a backlash between a cam of a camshaft and a corresponding rod of the valve. Regular check and adjustment клапанных backlashes therefore are not required. However it is necessary to use engine oil of high quality and recommended viscosity and to replace it with demanded periodicity. At start-up of the cold engine there is the small delay caused by alignment of pressure of engine oil in all parts of the engine, especially in hydraulic pushers. Valves can approximately knock 10 seconds then start to work silently.
If the engine was not started up by some days, valves can knock during longer time as almost all oil flows down from the top part of the engine and working surfaces of bearings. At this time it is necessary to be careful not to damage the engine: to avoid sharp change of power setting while all pushers will not be filled with engine oil. At warming up of the engine frequency of rotation of idling (a maximum from 2000 to 2500 mines-1) should not raise within 2 minutes or knock of valves will not stop yet. If noise of pushers does not stop, stop the engine and execute following actions (the engine temperature should be not less than 80 °С).
Uncover heads of the block of cylinders.
Turn a cranked shaft until the cam over a checked pusher will not be established directly upwards.

Fig. 3.1–91. Check of a free wheeling of a pusher

Press a pusher a wooden or plastic wedge (fig. 3.1–91). If the free wheeling of a pusher is more 0,2 mm, it is necessary to replace pushers.
Establish a cover of a head of the block of cylinders.
Wait approximately 30 minutes before engine start-up. It is necessary that work of hydraulic pushers, differently pistons was stabilised will hit about valves.

Processing of saddles of valves
Saddles of valves with wear tracks or подгорания are necessary for processing with obligatory preservation of corners and facet sizes.

Fig. 3.1–92. Is minimum admissible distance from an end face of the valve to the top surface of a head of the block of cylinders

If the valve saddle is necessary for processing, define a maximum quantity of metal which can be removed. If the excessive quantity of metal is removed, work of hydraulic pushers will be broken. Insert the valve into directing plug and press it to a valve saddle. Measure distance from the end of a rod of the valve to the top surface of a head of the block of cylinders (fig. 3.1–92). Is minimum admissible distance and makes 33,8 mm for inlet valves and 34,1 mm for final valves. At excessive deterioration of a saddle of the valve it is necessary to replace a head of the block of cylinders.
After any processing of saddles it is necessary to grind in valves.

3.15. A camshaft

4. Petrol engines of 3,7 and 4,2 l