Exhaust system — removal and installation (BMW 3 Series E46)

Note: During installation, it will be necessary to replace the gaskets between the inlet pipe and the manifold, as well as the nuts securing the inlet pipe.

Removal

1. Raise the front of the car and place it on reliable supports. Remove the crankcase guard from under the engine.

2. On the N42 engine, trace the oxygen sensor wiring and disconnect its electrical connector. Release the wiring from the fasteners.

3. On all models, unscrew the nuts securing the inlet pipe to the manifold and disconnect the inlet pipe. Remove the gasket (Fig. 14.3).



4. Loosen the clamp bolt that connects the two halves of the exhaust pipe support to the bracket attached to the gearbox. Then loosen the support axle bolt, turn the lower half of the support and release the pipe (Fig. 14.4).



5. Unscrew the bolts and remove the reinforcement plates fixed across the tunnel (Fig. 14.5). Note: there is a rubber support for the exhaust system on the rear plate.





6. Remove the rear rubber mounts from the exhaust system.

7. Remove the entire exhaust system assembly from under the vehicle.

8 To remove the heat shield, unscrew the bolts that secure it and lower the shield to the ground.

Installation

9. Installation of the exhaust system is carried out in the reverse order, taking into account the following notes.

• a) Install a new gasket where the intake pipe connects to the exhaust manifold. Also replace the intake pipe mounting nuts. Lubricate the manifold studs with copper-based grease.
• b) Check the position of the exhaust pipe relative to the cutout in the rear skirt of the body. If necessary, adjust the exhaust system supports to ensure the required clearance between the pipe and the cutout of the skirt.
• c) After installing the exhaust system on all supports, unscrew the bolts securing the support bracket to the gearbox and, if necessary, adjust the transverse position of the bracket within the elongated bolt holes so as to relieve tension in the exhaust system. After adjustment, tighten the bolts.