Catalytic Converter: Service and Repair
Exhaust Y-Pipe-Dual Catalytic ConverterMaterial:
Removal
All engines
CAUTION: Do not use oil or grease-based lubricants on isolators as they cause deterioration of rubber.
NOTE: The exhaust Y-pipe-dual catalytic converter is a 2-piece assembly. The RH and LH converters can be serviced separately as needed.
1. With the vehicle in NEUTRAL, position it on a hoist.
2. If equipped, remove the skid plate.
4.6L and 5.4L engines
3. Disconnect the LH heated oxygen sensor (HO2S) electrical connector.
All engines
4. Disconnect the catalyst monitor sensors electrical connectors.
5. NOTE: Whenever the exhaust Y-pipe - dual catalytic converter-to-exhaust intermediate pipe coupling is loosened, a new exhaust Y-pipe -dual catalytic converter-to-exhaust intermediate pipe coupling must be installed.
Loosen the exhaust Y-pipe-dual catalytic converter-to-exhaust intermediate pipe coupling. Slide the coupling back onto the intermediate pipe.
6. Loosen the RH catalytic converter-to-LH catalytic converter clamp.
7. NOTE: 4.6L and 5.4L shown, 4.2L similar.
Remove the nuts on the LH catalytic converter-to-exhaust manifold Joint.
8. NOTE: 4.6L and 5.4L shown, 4.2L similar.
Remove the nuts on the RH catalytic converter-to-exhaust manifold Joint.
4.6L and 5.4L engines
9. Let the RH catalytic convert drop down slightly and then disconnect the RH HO2S electrical connector.
All engines
10. NOTE: LH side shown, RH similar.
Remove the heat shield bolts from the transmission crossmember.
4.6L and 5.4L engines
11. NOTE: A special tool is available for use in removing the HO2S. An open-end wrench can be used for ease of removal.
NOTE: If necessary, lubricate the HO2S with penetrating and lock lubricant to assist in removal.
Remove the 2 HO2S.
All engines
12. NOTE: A special tool is available for use in removing the catalyst monitor sensors. An open-end wrench can be used for ease of removal.
NOTE: If necessary, lubricate the HO2S with penetrating and lock lubricant to assist in removal.
Remove the 2 catalyst monitor sensors.
13. Remove the exhaust Y-pipe-dual catalytic converter hanger bracket and isolator bolts.
14. Remove the RH catalytic converter.
15. Remove the LH catalytic converter.
Installation
CAUTION: Do not tighten the fasteners until all components are assembled and aligned, making sure to tighten all fasteners beginning at the front of the vehicle.
NOTE: Clean the mating surfaces of the manifold outlet flare and the catalytic converter inlet flare.
Make sure not to damage the manifold outlet flare, the converter inlet flare or the studs.
All engines
1. NOTE: Use caution installing the catalytic converter. Make sure not to damage the manifold outlet flare, the converter inlet flare or the studs.
Position the RH catalytic converter.
4.6L and 5.4L engines
2. NOTE: Make sure to apply anti-seize lubricant to the threads of the sensors before installation.
NOTE: A special tool is available for use in installing the HO2S. An open-end wrench can be used for ease of installation.
Install the RH HO2S sensors.
^ Tighten to 40 Nm (30 ft. lbs.).
All engines
3. NOTE: Make sure to apply anti-seize lubricant to the threads of the sensors before installation.
NOTE: A special tool is available for use in installing the catalyst monitor sensor. An open-end wrench can be used for ease of installation.
Install the RH catalyst monitor.
^ Tighten to 40 Nm (30 ft. lbs.).
4. Loosely install the exhaust Y-pipe-dual catalytic converter hanger bracket and isolator and RH exhaust Y-pipe-dual catalytic converter hanger bracket and isolator bolt. Let the LH side of the exhaust Y-pipe-dual catalytic converter hanger bracket and isolator hang down.
4.6L and 5.4L engines
5. Connect the RH HO2S sensor electrical connector.
All engines
6. NOTE: Use caution installing the catalytic converter. Make sure not to damage the manifold outlet flare, the converter inlet flare or the studs.
Using an abrasive pad, clean the exhaust clamp surface area of any surface rust.
^ Position the LH catalytic converter and loosely install the exhaust manifold nuts.
7. NOTE: Make sure to apply anti-seize lubricant to the threads of the sensors before installation.
NOTE: A special tool is available for use in installing the catalyst monitor sensor. An open-end wrench can be used for ease of installation.
Install the LH catalyst monitor sensor.
^ Tighten to 40 Nm (30 ft. lbs.).
4.6L and 5.4L engine
8. NOTE: Make sure to apply anti-seize lubricant to the threads of the sensors before installation.
NOTE: A special tool is available for use in installing the HO2S. An open-end wrench can be used for ease of installation.
Install the LH HO2S sensor.
^ Tighten to 40 Nm (30 ft. lbs.).
All engines
9. Loosely install the bolt for the LH side of the exhaust Y-pipe-dual catalytic converter hanger bracket and isolator.
10. NOTE: Use caution installing the catalytic converter. Make sure not to damage the manifold outlet flare, the converter inlet flare or the studs.
Push the RH catalytic converter into place and loosely install the exhaust manifold nuts.
11. NOTE: Using an abrasive pad, clean the exhaust coupling surface area of any surface rust.
NOTE: Whenever the exhaust Y-pipe - dual catalytic converter-to-exhaust intermediate pipe coupling is loosened, a new exhaust Y-pipe -dual catalytic converter-to-exhaust intermediate pipe coupling must be installed.
Loosely slide the exhaust Y-Pipe-dual catalytic converter-to-exhaust intermediate pipe coupling into place.
12. NOTE: 4.6L and 5.4L shown, 4.2L similar.
Tighten the LH catalytic convert-to-exhaust manifold nuts in the following sequence.
^ Tighten the lower nut to 20 Nm (15 ft. lbs.).
^ Tighten the upper nut to 40 Nm (30 ft. lbs.).
^ Tighten the lower nut to 40 Nm (30 ft. lbs.).
13. NOTE: 4.6L and 5.4L shown, 4.2L similar.
Tighten the RH catalytic convert-to-exhaust manifold nuts in the following sequence.
^ Tighten the lower nut to 20 Nm (15 ft. lbs.).
^ Tighten the upper nut to 40 Nm (30 ft. lbs.).
^ Tighten the lower nut to 40 Nm (30 ft. lbs.).
14. NOTE: LH side shown, RH similar.
Tighten the heat shield bolts to the transmission crossmember.
^ Tighten to 15 Nm (11 ft. lbs.).
4.6L and 5.4L engines
15. Connect the LH HO2S sensor electrical connectors.
All engines
16. Connect the 2 catalyst monitor sensor electrical connectors.
17. If equipped, install the skid plate.
18. Align the exhaust system and tighten the exhaust system clamps.