This procedure covers the removal and replacement of the direct-fit catalytic converter on a 2011-2014 Ford F-150 with the 3.5L EcoBoost V6 engine.

Warnings

Tools required

Parts

• Direct-fit catalytic converter assembly × 1 — Use OEM specification or EPA-compliant aftermarket
• Exhaust flange gaskets × 2 — Use OEM specification
• Oxygen sensor (if damaged) × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and allow exhaust system to cool completely (minimum 2 hours after last operation)
2. Place wheel chocks behind rear wheels
3. Apply penetrating oil to all exhaust flange bolts, O2 sensor threads, and hanger bolts. Allow to soak for at least 30 minutes
4. Raise front of vehicle and support securely on jack stands rated for vehicle weight
5. Remove plastic undertray/skid plate if equipped to access catalytic converter
6. Identify which catalytic converter requires replacement (driver side/Bank 1 or passenger side/Bank 2)

Procedure

1. 1

   Disconnect oxygen sensors
   Locate the upstream and downstream oxygen sensors on the catalytic converter being replaced. Disconnect the electrical connectors by pressing the release tabs and pulling straight apart. Using the O2 sensor socket, carefully remove both oxygen sensors from the catalytic converter. Turn counterclockwise to remove. If sensors are stuck, apply additional penetrating oil and allow to soak, then use a wrench on the socket for additional leverage.
   ⚠O2 sensors are fragile. Excessive force can damage the sensor element. Do not use impact tools.
2. 2

   Remove heat shield bolts
   Remove the heat shield covering the catalytic converter by removing all mounting bolts. The heat shield is typically secured with 3-5 bolts depending on configuration. Use a socket or wrench to remove the bolts and set the heat shield aside. Inspect the heat shield for damage and reuse if in good condition.
3. 3

   Disconnect upstream exhaust flange
   Locate the exhaust flange connection between the turbocharger downpipe and the catalytic converter inlet. Remove the two or three flange bolts securing this connection. Support the catalytic converter weight with one hand or a support stand while removing the final bolt. Once bolts are removed, separate the flange connection. The old gasket will likely remain stuck to one flange surface.
   ⚠Catalytic converter may shift when flange is disconnected. Ensure adequate support to prevent sudden movement.
4. 4

   Disconnect downstream exhaust flange
   Move to the rear of the catalytic converter where it connects to the intermediate pipe or muffler assembly. Remove the flange bolts at this connection point. Once bolts are removed, separate the flange. Remove and discard the old gasket material from both flange surfaces.
5. 5

   Remove exhaust hanger supports
   Locate the rubber exhaust hangers supporting the catalytic converter assembly. Using a pry bar or by hand, disconnect the exhaust pipe from the rubber hangers. There are typically 1-2 hanger points on the catalytic converter section. Note the orientation of hangers for reassembly.
6. 6

   Remove old catalytic converter
   With all connections disconnected, carefully lower and remove the catalytic converter assembly from the vehicle. Maneuver it out from between the frame rails and suspension components. The converter is heavy (approximately 20-30 lbs) and may require repositioning to clear obstructions.
7. 7

   Clean flange surfaces
   Using a wire brush and scraper, thoroughly clean all gasket material and carbon deposits from both the upstream and downstream exhaust flange mating surfaces. The surfaces must be completely clean and flat for proper sealing. Inspect flange faces for warping or damage.
8. 8

   Install oxygen sensors in new converter
   Apply a thin coat of anti-seize compound to the threads of both oxygen sensors. Thread only - do not get anti-seize on the sensor element. Thread the upstream and downstream O2 sensors into the new catalytic converter by hand until snug. Use the O2 sensor socket and torque wrench to tighten to specification.
   ⚠Never apply anti-seize to the sensor element or electrical connector. Apply only to threads.
   Torque spec

   O2 Sensor45 Nm (33 lb-ft)
9. 9

   Position new catalytic converter
   Maneuver the new catalytic converter assembly into position under the vehicle. Align the inlet flange with the turbocharger downpipe and the outlet flange with the intermediate pipe. Reconnect the exhaust hangers to the rubber isolators to support the assembly weight.
10. 10

    Install upstream flange connection
    Position a new exhaust gasket between the upstream flange surfaces (turbocharger downpipe to catalytic converter). Insert flange bolts and start them by hand. Apply anti-seize compound to bolt threads. Do not fully tighten yet - leave bolts snug to allow for alignment adjustment.
11. 11

    Install downstream flange connection
    Position a new exhaust gasket between the downstream flange surfaces (catalytic converter to intermediate pipe). Insert flange bolts and start them by hand. Apply anti-seize compound to bolt threads. Snug bolts but do not torque yet to allow for final alignment.
12. 12

    Torque all flange connections
    Starting with the upstream flange, torque all exhaust flange bolts to specification in a cross-pattern to ensure even pressure distribution. Then torque the downstream flange bolts in the same manner. Verify that both flanges are seated evenly with no gaps. If your upstream connection is to the turbocharger, use 45 Nm specification. If connecting to other exhaust components, use 55 Nm specification as appropriate.
    Torque spec

    Exhaust Flange Bolts45 Nm (33 lb-ft)
13. 13

    Reinstall heat shield
    Position the heat shield over the catalytic converter and align all mounting holes. Install all heat shield bolts and tighten to specification using a torque wrench. Ensure the heat shield does not contact the catalytic converter body directly.
    Torque spec

    Heat Shield Bolts10 Nm (7 lb-ft)
14. 14

    Reconnect oxygen sensor connectors
    Locate the O2 sensor electrical connectors and reconnect them to their respective sensors. Route wiring away from hot exhaust components and secure with existing clips. Ensure connectors are fully seated and locked with an audible click.

Reassembly

1. Reinstall plastic undertray or skid plate if removed
2. Lower vehicle from jack stands
3. Double-check that all tools and parts have been removed from under vehicle

Verification

• Start engine and allow to idle. Listen for exhaust leaks at both flange connections. A hissing sound indicates a leak requiring re-torquing or gasket replacement
• Visually inspect all connections while engine is running for signs of exhaust gas escaping
• Allow engine to reach operating temperature and verify no unusual odors or smoke from exhaust area
• Use an OBD-II scanner to verify no oxygen sensor codes are present (P0420, P0430, P0134, P0154, etc.)
• Test drive vehicle and verify normal engine performance and no check engine light illumination
• After 50-100 miles of driving, re-inspect all flange bolts and re-torque if necessary

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