Exhaust Manifold: Service and Repair

WM 261019 Removing and installing exhaust manifold on 4.8-litre DFI engines

Technical values





Preliminary work

1. Remove engine. -> 100119 Removing and installing V8 4.8-litre DFI engine - section on "Removing" 100119 Removing and installing V8 4.8-litre DFI engine
2. Remove primary catalytic converter. For details, see -> 267619 Removing and installing primary catalytic converter on V8 4.8-litre DFI engines - section on "Removing" 267619 Removing and installing primary catalytic converter on 4.8-litre V8 DFI engines

Removing exhaust manifold

1. Remove heat protection panels on the exhaust manifold and on the generator. -arrows-





Heat protection panels

2. Unclip the lambda sensor cable from all holders. Remove lambda sensor when replacing the exhaust manifold. Cylinders 1 to 4 => Lambda sensor on naturally aspirated engine M48/01, cylinders 1 to 4 , cylinders 5 to 8 => Lambda sensor on naturally aspirated engine M48/01, cylinders 5 to 8.





Lambda sensor on naturally aspirated engine M48/01, cylinders 1 to 4









Lambda sensor on naturally aspirated engine M48/01, cylinders 5 to 8





3. Spray fastening nuts on the exhaust manifold with anti-rust agent if necessary.
4. Loosen the fastening nuts in reverse order to the sequence shown below => Tightening sequence for exhaust manifold on naturally aspirated engine M48/01, cylinders 1 to 4. Remove exhaust manifold. Replace fastening nuts.





Tightening sequence for exhaust manifold on naturally aspirated engine M48/01, cylinders 1 to 4

5. Remove and replace seal. Clean sealing faces. Cylinders 1 to 4 => Exhaust manifold on naturally aspirated engine M48/01, cylinders 1 to 4 , cylinders 5 to 8 => Exhaust manifold on naturally aspirated engine M48/01, cylinders 5 to 8.





Exhaust manifold on naturally aspirated engine M48/01, cylinders 1 to 4









Exhaust manifold on naturally aspirated engine M48/01, cylinders 5 to 8






Installing exhaust manifold

Information

- Visually inspect exhaust manifold for cracks and distortion.

- A cracked or distorted exhaust manifold must not be reinstalled.

- As a matter of principle, replace seals on manifold.

- Replace the studs in the cylinder head if damaged. Measure the studs with respect to the cylinder head and fit new studs to the same screw-in depth as the old studs.

1. Clean sealing surfaces. The surfaces must be free from foreign objects.
2. Fit lambda sensor when replacing the exhaust manifold (grease the thread of the lambda sensor with a light coating of grease 000.043.207.07, status 06/07).
3. Use a new seal. The seal must be positioned so that the part number is visible from the outside. => Exhaust manifold on naturally aspirated engine M48/01, cylinders 1 to 4 => Exhaust manifold on naturally aspirated engine M48/01, cylinders 5 to 8
Slide the exhaust manifold over the studs and fit it using new fastening nuts. Tighten the fastening nuts to the prescribed tightening torque. Observe tightening sequence. => Tightening sequence for exhaust manifold on naturally aspirated engine M48/01, cylinders 1 to 4





Tightening sequence for exhaust manifold on naturally aspirated engine M48/01, cylinders 1 to 4





Exhaust manifold on naturally aspirated engine M48/01, cylinders 1 to 4









Exhaust manifold on naturally aspirated engine M48/01, cylinders 5 to 8





4. Clip lambda sensor cable into the holders. => Lambda sensor on naturally aspirated engine M48/01, cylinders 1 to 4 => Lambda sensor on naturally aspirated engine M48/01, cylinders 5 to 8





Lambda sensor on naturally aspirated engine M48/01, cylinders 1 to 4









Lambda sensor on naturally aspirated engine M48/01, cylinders 5 to 8





5. Fit heat protection panels. => Heat protection panels on V8 naturally aspirated engine





Heat protection panels on V8 naturally aspirated engine

Subsequent work

1. Install primary catalytic converter. For details, see -> 267619 Removing and installing primary catalytic converter on V8 4.8-litre DFI engines - section on "Installing" 267619 Removing and installing primary catalytic converter on 4.8-litre V8 DFI engines
2. Install engine. -> 100119 Removing and installing V8 4.8-litre DFI engine - section on "Installing" 100119 Removing and installing V8 4.8-litre DFI engine