Front Exhaust System With Catalytic Converter
Front Exhaust System With Catalytic Converters, B235L/E/RTo remove
1. Remove the upper engine cover.
2. Remove the bypass pipe with valve.
Note: There is an O-ring at the bypass pipe's attachment to the turbo intake pipe.
3. Remove the exhaust manifold's heat shield.
4. Unplug the connectors to the oxygen sensors. Cut off the cable tie and pull out the cables.
5. Loosen the two upper nuts at the connection between the turbo/front exhaust system.
6. Raise the car.
7. Loosen the third nut at the connection between the turbo/front exhaust system.
8. Undo the upper bolt on the stay securing the catalytic converter to the engine.
9. Separate the pipe joint between the front and rear exhaust systems.
10. Remove the clips and carefully pull away the rubber mountings
11. Lower the front exhaust system.
Important: The flexible section at the front of the exhaust system should not be bent out of line by more than 5°, i.e. if the front exhaust system is allowed to hang, it must not bend more than the sag caused by its own weight.
If the pipe is overloaded, permanent deformation of the components will result. This can cause noise and leakage, and damage at a later stage.
To Fit
Important: When fitting the front exhaust system to the turbo, the nuts should be tightened alternately to avoid distorting the flange. The flange must not abut against the turbo connection flange.
Ensure that the system hangs straight so that no stresses occur during fitting.
Note: Coat the studs sparingly with Molycote 1000, part no. 30 20 971 or similar.
1. Fit the front pipe with rubber mountings and clips.
2. Fit the nuts on the rear pipe joints.
Tightening torque 22 Nm (16 ft. lbs.)
3. Fit the lower nut on the turbocharger.
4. Fit the stay securing the exhaust pipe to the engine.
Tightening torque 25 Nm (19 ft. lbs.)
5. Lift up the oxygen sensor cables and lower the car.
6. Fit the two upper nuts on the exhaust system.
Tightening torque 24 Nm (18 ft. lbs.)
7. Lay out the oxygen sensor cables and plug in the connectors.
8. Secure the cables with a cable tie.
9. Fit the upper engine cover and the heat shield over the exhaust manifold.
10. Lubricate the O-ring on the bypass pipe with acid-free Vaseline and fit the pipe with valve and vacuum hose.
Tightening torque 8 Nm (6 ft. lbs.)