Intake Manifold: Service and Repair

Removing and Installing Intake Air Manifold


Follow instructions for disconnecting and connecting battery, refer to Service Precautions.
Disconnect negative battery lead.

Remove intake filter housing with air-mass flow sensor.
Release wiring harness section for engine from intake air manifold and lay to one side with cable ducts.
If necessary, remove ASC+T throttle.
If necessary, disconnect Bowden cables for throttle actuation.
If necessary, remove throttle assembly.

Caution: Catch and dispose of escaping fuel.

Disconnect fuel feed and return lines from injection pipe.

Note: From 9/98 version without fuel return line.

Follow instructions for removing and installing fuel hoses, refer to Powertrain Management.





Remove connector for brake force booster.





Version up to 9/98
Remove clip and slide engine vent tube forwards.

Installation:
Check/replace sealing ring.





Version from 9/98
Press sliding piece on vent pipe (1) forward until it is no longer fixed to cover.





Version from 9/98
Keep vent pipe (1) pressed forward and lay towards bottom.





Version from 9/98

Installation:
Replace sealing ring (1) and coat with oil as anti-friction agent. Make sure sealing ring is correctly seated and is not crushed by vent pipe.
Feed vent pipe onto connection on cover.





Unfasten nuts (left and right). Remove decoupling elements and lift intake air manifold upwards to remove.





If necessary, remove vent pipe in intake air manifold:
Remove throttle valve.
Remove covers at front and rear from intake air manifold.

Note: Vent pipe is located with a lug (1) and locked with a retaining lug (2) in intake air manifold.

Carefully press retaining lug (2) back and push vent pipe out of bore.





Remove vent pipe (1).

Installation:
Replace seal.





Installation:
Insert vent pipe.
Check fixture (1) and lock (2) of vent pipe in intake air manifold.
Replace seals.
Install covers at front and rear.





Note: The intake air manifold is vibrationally separated from the cylinder head by decoupling elements and gaskets.
1. Nut
2. Decoupling element
3. Intake air manifold
4. Seal





Installation:
Check seals and replace if necessary.

Caution: Ensure that seals are correctly seated.





Installation:
Fit two decoupling elements on left and right with nuts and do not tighten (i.e. no preload).
Align intake air manifold.
Fit all other decoupling elements with nuts and tighten crosswise from inside to outside.




Tightening Torque