Catalytic Converter: Service and Repair

Removing And Installing Exhaust Manifold With Catalytic Converter

Technical values







Preliminary work

CAUTION:
Hot components
- Risk of burns
- Let hot components cool down.
- Wear personal protective gear.

1. Remove rear underbody panelling.

INFORMATION:
- The connecting cable can be turned by up to four turns when removing the lambda sensors.
- Also loosen the cable attachments at the heat shields on the cylinder head.

2. Detach blue cable for lambda sensor upstream of catalytic converter at the cylinder head.
2.1. Unscrew lambda sensors upstream of the catalytic converter at the exhaust manifold. The difficult (obscure) task of routing the cable at the bulkhead (belt side) is not required for this.







2.2. Unclip and open the plug connection -1- for the lambda sensor downstream of the catalytic converter (black cable -2- ) on the rear-axle cross member.
2.3. The lambda sensors must be converted when you install a new exhaust manifold with catalytic converter.
2.4. Grease thread of lambda sensors with Optimol Paste MF (Part No.: 000.043.207.07) before refitting them.

Removal

Removing exhaust manifold with catalytic converter

CAUTION:
Hot components
- Risk of burns Component overview
- Let hot components cool down.
- Wear personal protective gear.

Component overview







1. Unscrew three M8 lock nuts on the three-hole flange for the rear silencer. 1.1. Replace M8 lock nuts.

2. Unscrew nine external Torx screws (M8 x 21) -2- and remove exhaust manifold with catalytic converter -1-.







2.1. Remove and replace metal seal.

Repair solution - replacing threaded bolts on three-hole flange







1. Tap out damaged threaded bolts on the three-hole flange with a hammer.
2. Use M8 x 30 hexagon-head bolt (Part No. 900.075.365.02) instead of the threaded bolt.

Installation

Installing exhaust manifold with catalytic converter
1. Fit exhaust manifold with new metal seal and new lock nuts on the three-hole flange for the silencer.
2. Fit exhaust manifold with new metal seal and nine external Torx screws on the cylinder head flange.







2.1. The tab of the metal seal -arrow- must be facing the cylinder head.







2.2. Tighten external Torx screws (M8 x 21) -2- evenly at first according to the specified tightening sequence.
2.3. Tighten screws to the prescribed torque and according to the specified tightening sequence.

3. Tighten new M8 lock nuts on the three-hole flange.

Tightening specifications







1. First fit external Torx screws on the cylinder head and tighten according to the specified tightening sequence -1 to 9-. - Tightening torque: 23 Nm (17 ftlb.)
1.1. Then tighten new M8 lock nuts on the three-hole flange. - Tightening torque: 23 Nm (17 ftlb.)

Subsequent work

INFORMATION:
- The connecting cable can be turned by up to four turns when removing the lambda sensors.
- Also loosen the cable attachments at the heat shields on the cylinder head.

1. Fit lambda sensor upstream of catalytic converter.
1.1. Grease thread of lambda sensors with Optimol Paste MF (Part No.: 000.043.207.07) before refitting them.
1.2. Turn connecting cable (blue) anti-clockwise by four turns and screw in and tighten lambda sensor. - Tightening torque: 50 Nm (37 ftlb.)
1.3. Secure connecting cable (blue) on the heat shield with a new tie-wrap.

2. Route cable for lambda sensor downstream of catalytic converter.







2.1. Connect and clip in plug connection -1- for the lambda sensor downstream of the catalytic converter (black cable -2- ) on the rear-axle cross member.

3. Install rear underbody panelling.