Muffler (A4 Sedan)
1. Additional muffler: in the factory configuration, a single unit with additional. muffler, in case of repair it is replaced separately; align the system. exhaust gas discharge without mechanical stress.
2. Nut: 25 Nm.
3. Rear clamp: Align the system before tightening. exhaust gas discharge without mechanical stress; tighten threaded connections evenly.
4. Bolt: 23 Nm.
5. Holder.
6. Mounting loop: replace if damaged.
7. Nut: 25 Nm.
8. Double clamp, front: align the system before tightening. exhaust gas discharge without mechanical stress; tighten threaded connections evenly.
9. Gasket: replace.
10. Nut: 25 Nm.
11. Catalyst: protect the catalyst from impacts and jolts; align the system. exhaust gas discharge without mechanical stress.
12. Nut: 40 Nm; replace; lubricate the turbocharger locating pins with heat-resistant paste.
13. Gasket: replace.
14. Lambda probe "G39" and heating element of lambda probe "Z19": the threads of new lambda probes are lubricated with mounting paste; when reusing the same lambda probe, lubricate its threads with heat-resistant paste; heat-resistant paste; mounting and heat-resistant pastes must not get into the grooves of the probe body.
15. Lambda probe after catalytic converter "G130" and heating of lambda probe 1 after catalytic converter "Z29": the threads of the new lambda probes are lubricated with mounting paste; when reusing the same lambda probe, lubricate its threads with heat-resistant paste; heat-resistant paste; mounting and heat-resistant pastes must not get into the grooves of the probe body.
16. Intermediate muffler: with a detachable element; depending on the version, a front exhaust pipe may be installed instead of the front muffler; align the system. exhaust gas discharge without mechanical stress.
17. Downpipe: with detachable element; depending on the version, a front muffler may be installed instead of the exhaust pipe; align the system. exhaust gas discharge without mechanical stress.
18. Bolt; 23 Nm.
19. Suspension mount: replace if damaged; check pre-tension.
20. Middle muffler: in the factory configuration, a single unit with additional. muffler, in case of repair it is replaced separately; align the system. exhaust gas discharge without mechanical stress.
21. Suspension mount: replace if damaged. check pre-tension.
22. Bolt: 23 Nm.
23. Exhaust pipe: replace separately during repairs; the point of separation between the rear muffler and the muffler outlet pipe.
24. Clamp; 60 Nm.
Mounting position of the front clamp
Install the clamp clamp taking into account the angle as shown in the figure.
The threaded connections face right. The nuts are facing upwards. α = approx. 20°.
Mounting position of the rear clamping clamp
Install the clamp so that the ends of the bolts do not extend beyond the bottom edge of the clamp.
The connections are facing downwards.
Removal and installation the catalytic converter
Disconnect the lambda probe connector after the "G130" catalytic converter and the lambda probe heating element 1, after the "Z29" catalytic converter and release the wires. Disconnect the connector of the lambda probe "G39" and the heating element of the lambda probe "Z19" and release the wires.
Disconnect connector "1" of air flow meter "G70". Release air intake pipe "2". Remove air flow meter housing. filters with the arrow pointing upwards. Remove the sound insulation.
Cars with independent heater: Clamp the coolant line of the independent heater at the top with hose clamps up to 25 mm "3094" and disconnect. Unscrew the coolant lines from the body "1".
Clamp the coolant line of the independent heater from below using hose clamps up to 25 mm "3094" and disconnect. Unscrew the coolant lines "1" from the body and remove them.
All
Remove the downpipe/front muffler. Disconnect threaded connection "1", unscrew bolt "2" and remove the catalytic converter mount.
Loosen the arrow bolts and remove the heat shield of the right drive shaft.
Unscrew the "arrow" nuts and remove the turbocharger upwards.
Installation
Installation in reverse order. Replace all seals, gaskets and self-locking nuts. Install the downpipe/front muffler.
Cars with independent heater: Bleed the independent heater.
Muffler (A4 Avant)
1. Gasket: replace.
2. Lambda probe "G39" and heating element of lambda probe "Z19": the threads of new lambda probes are lubricated with mounting paste; when reusing the same lambda probe, lubricate its threads with heat-resistant paste; heat-resistant paste; mounting and heat-resistant pastes must not get into the grooves of the probe body.
3. Lambda probe after catalytic converter "G130" and heating of lambda probe 1 after catalytic converter "Z29": the threads of the new lambda probes are lubricated with mounting paste; when reusing the same lambda probe, lubricate its threads with heat-resistant paste; heat-resistant paste; mounting and heat-resistant pastes must not get into the grooves of the probe body.
4. Catalyst: protect the catalyst from impacts and shocks; align the system. exhaust gas discharge without mechanical stress.
5. Intermediate muffler: align the system. exhaust gas discharge without mechanical stress.
6. Double clamp, front: align the system before tightening. exhaust gas discharge without mechanical stress; tighten threaded connections evenly.
7. Nut: 23 Nm.
8. Middle muffler: installed at the factory as one piece with the rear mufflers, in case of repair it is replaced separately; to remove, remove the diagonal brace; align the system. exhaust gas discharge without mechanical stress.
9. Rear left clamp: for replacing the middle and rear mufflers separately; align the system before tightening. exhaust gas discharge without mechanical stress; tighten the connections evenly.
10. Main muffler, left: in the initial configuration, a structural unit with a middle muffler and an end pipe; to remove, remove the diagonal brace; in case of repair, the middle muffler, final muffler and final section are replaced separately; align the system. exhaust gas discharge without mechanical stress.
11. Exhaust pipe: in the factory configuration, a single unit with additional. muffler, in case of repair it is replaced separately.
12. Clamp: 23 Nm.
13. Suspension mount: replace if damaged. check pre-tension.
14. Nut: replace; 20 Nm.
15. Nut: 23 Nm.
16. Main muffler, right: in the initial configuration, a structural unit with a middle muffler and an end pipe; to remove, remove the diagonal brace; in case of repair, the middle muffler, final muffler and final section are replaced separately; align the system. exhaust gas discharge without mechanical stress.
17. Rear right clamp: for replacing the middle and rear mufflers separately; align the system before tightening. exhaust gas discharge without mechanical stress; tighten the connections evenly.
18. Bolt: replace; 20 Nm.
19. Suspension mount: replace if damaged; check pre-tension.
20. Gasket: replace.
21. Nut: 25 Nm.
22. Nut: 40 Nm; replace; lubricate the turbocharger locating pins with heat-resistant paste.
Mounting position of the rear clamping clamp
Install the clamping clamps so that the end of the bolt does not extend beyond the bottom edge of the clamping clamp. Mounting position: threaded connections facing forward.