This procedure covers removal and replacement of the intermediate pipe section of the exhaust system on a 2021-2024 Ford F-150 with the 3.5L EcoBoost V6 engine.

Warnings

Tools required

Parts

• Intermediate pipe assembly × 1 — Use OEM specification
• Exhaust flange gaskets × 2 — Use OEM specification
• Exhaust hanger isolators (if worn) × 2 — Use OEM specification

Preparation

1. Park vehicle on level surface and allow exhaust system to cool completely (minimum 2 hours after operation).
2. Raise vehicle securely on lift or jack stands to provide adequate working clearance underneath.
3. Spray all exhaust flange bolts and hanger bolts with penetrating oil and allow to soak for 15-30 minutes.
4. Inspect intermediate pipe for exact connection points and note any oxygen sensor locations that may need disconnection.

Procedure

1. 1

   Disconnect oxygen sensors (if equipped on intermediate pipe)
   Locate any oxygen sensors mounted on the intermediate pipe section. Disconnect the electrical connectors by pressing the release tab and pulling apart. If removing sensors, use a 22mm oxygen sensor socket and turn counterclockwise to remove. Mark sensor positions if multiple sensors are present.
2. 2

   Remove heat shield (if equipped)
   If a heat shield covers the intermediate pipe, remove the mounting bolts using a 10mm socket. Note the position and orientation of the heat shield for reinstallation. Set shield and bolts aside.
   Torque spec

   Heat Shield Bolts10 Nm (7 lb-ft)
3. 3

   Support intermediate pipe
   Position a jack or support stand under the intermediate pipe to support its weight during removal. This prevents the pipe from falling when disconnected and reduces stress on remaining connections during disassembly.
4. 4

   Disconnect front flange connection
   Locate the front flange connection where the intermediate pipe connects to the catalytic converter or front pipe. Remove the flange bolts using a 15mm socket. There are typically 2-3 bolts securing this connection. Once removed, separate the flange and remove the old gasket.
   ⚠If bolts are severely corroded, use caution to avoid breaking them. Heat may be required for stubborn fasteners.
   Torque spec

   Exhaust Flange Bolts45 Nm (33 lb-ft)
5. 5

   Disconnect rear flange connection
   Move to the rear flange where the intermediate pipe connects to the rear exhaust section. Remove the flange bolts using a 15mm socket. Separate the flange connection and remove the old gasket. Inspect both flange surfaces for damage.
   Torque spec

   Exhaust Flange Bolts45 Nm (33 lb-ft)
6. 6

   Remove exhaust hanger connections
   Locate the rubber hanger isolators supporting the intermediate pipe. Remove the hanger bolts using a 13mm socket, or use a pry bar to carefully separate the exhaust hanger from the rubber isolator. Note the number and position of all hangers for reinstallation.
   Torque spec

   Hanger Bolts23 Nm (17 lb-ft)
7. 7

   Remove intermediate pipe
   With all connections disconnected, carefully lower and remove the intermediate pipe from the vehicle. Maneuver as needed to clear crossmembers and other components. Inspect the removed pipe for damage, cracks, or excessive corrosion.
8. 8

   Clean flange surfaces and inspect components
   Use a wire brush to thoroughly clean both front and rear flange mating surfaces on the remaining exhaust components. Remove all old gasket material and corrosion. Inspect flange surfaces for warping or damage. Inspect rubber hanger isolators and replace if torn or excessively worn.
9. 9

   Prepare new intermediate pipe
   Compare new intermediate pipe to the old unit to verify correct application. Install new flange gaskets onto the new pipe. Apply anti-seize compound to all flange bolt threads. If oxygen sensors were removed, apply anti-seize to sensor threads only (avoiding the sensor tip).
10. 10

    Position and support new intermediate pipe
    Maneuver the new intermediate pipe into position under the vehicle. Use a jack or support stand to hold the pipe at the correct height for connection. Align the front flange connection first, ensuring the gasket is properly positioned.
11. 11

    Install front flange connection
    Install the front flange bolts finger-tight, ensuring the gasket remains properly positioned. Once all bolts are started, tighten them in a cross-pattern to the specified torque using a torque wrench. Verify the flange is seated evenly.
    Torque spec

    Exhaust Flange Bolts45 Nm (33 lb-ft)
12. 12

    Install rear flange connection
    Align the rear flange connection and install bolts finger-tight with the gasket properly positioned. Tighten bolts in a cross-pattern to the specified torque. Check alignment to ensure no binding or stress on the exhaust system.
    Torque spec

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

    Connect exhaust hangers
    Attach the intermediate pipe to the rubber hanger isolators. Install and torque hanger bolts to specification. If using slip-on style hangers, use a pry bar to stretch the rubber isolator over the exhaust hanger. Ensure the pipe hangs evenly with adequate clearance from all components.
    Torque spec

    Hanger Bolts23 Nm (17 lb-ft)
14. 14

    Install oxygen sensors and heat shield
    If oxygen sensors were removed, install them into the new intermediate pipe and torque to specification. Connect the electrical connectors ensuring they click securely. If equipped with a heat shield, position it correctly and install the mounting bolts, torquing to specification.
    Torque spec

    O2 Sensor45 Nm (33 lb-ft)

    Heat Shield Bolts10 Nm (7 lb-ft)

Reassembly

1. Remove all tools and support stands from under the vehicle.
2. Verify all exhaust connections are secure and properly torqued.
3. Check for adequate clearance between exhaust components and fuel lines, brake lines, and body panels throughout the full range of suspension travel.
4. Verify all electrical connections for oxygen sensors are secure and routed away from heat and moving components.

Verification

• Lower vehicle to the ground safely.
• Start the engine and listen for exhaust leaks at all flange connections. A hissing sound indicates a leak that must be corrected.
• Perform a visual inspection under the vehicle while the engine is running to check for exhaust gas escaping from connections.
• Allow the engine to reach operating temperature and verify no exhaust odors enter the cabin.
• After the first 50-100 miles of driving, re-inspect all flange connections for tightness and check for any signs of exhaust leaks or abnormal noises.

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