This procedure covers removal and replacement of the muffler on a 2011-2014 Ford F-150 with 3.5L EcoBoost V6 engine, including disconnection from intermediate pipes and reinstallation with new hardware.

Warnings

Tools required

Parts

• Muffler assembly × 1 — Use OEM Ford specification or equivalent aftermarket (Walker/Magnaflow)
• Exhaust flange gasket × 1 — Ford FL3Z-5A231-A or equivalent
• Muffler clamp(s) × 2 — As needed if reusing is not possible
• Exhaust hanger isolators × 3 — Replace if cracked or degraded

Preparation

1. Park vehicle on level, solid surface and engage parking brake
2. Place wheel chocks behind rear wheels
3. Allow exhaust system to cool completely (minimum 2 hours after last engine operation)
4. Raise rear of vehicle using floor jack at rear axle or frame contact points
5. Support vehicle securely with jack stands under frame rails behind rear axle
6. Spray all exhaust fasteners (flange bolts, clamp bolts, hanger bolts) with penetrating oil and allow 15-20 minutes soak time
7. Visually inspect muffler location and identify all connection points: inlet flange, outlet clamp or flange, and rubber hanger mounts

Procedure

1. 1

   Disconnect outlet pipe connection
   Locate the connection between the muffler outlet and the tailpipe/tip assembly. If equipped with a clamp connection, use a 13mm socket to loosen the clamp bolts completely. If equipped with a flanged connection, remove the flange bolts. Separate the connection - you may need to twist the pipes slightly or use a rubber mallet to break the seal.
   Torque spec

   Muffler Clamps55 Nm (41 lb-ft)
2. 2

   Disconnect inlet flange connection
   Locate the inlet flange where the Y-pipe or intermediate pipe connects to the muffler inlet. Use a 15mm socket to remove the two or three flange bolts securing this connection. Support the muffler with one hand as you remove the final bolt to prevent it from dropping. Separate the flange connection and remove the old gasket.
3. 3

   Remove front hanger support
   Locate the rubber hanger isolator near the front of the muffler (typically on the driver side). Use a pry bar or your hands to carefully pop the muffler hanger rod out of the rubber isolator. The isolator remains attached to the vehicle frame.
4. 4

   Remove middle hanger support
   Locate the center rubber hanger isolator supporting the muffler body. Carefully disconnect the muffler hanger rod from the rubber isolator using a pry bar or by hand. Work the rod out of the isolator slot - avoid tearing the rubber.
5. 5

   Remove rear hanger support and lower muffler
   Locate the rear-most rubber hanger isolator near the muffler outlet. Disconnect the hanger rod from the isolator. With all connections now free, carefully lower the muffler assembly from the vehicle. Maneuver it out from between the frame rails and set aside.
6. 6

   Inspect and clean mounting points
   Inspect all rubber hanger isolators for cracks, tears, or excessive wear - replace any degraded isolators now. Use a wire brush to clean the inlet flange mating surface on the intermediate pipe, removing all old gasket material and corrosion. Clean the outlet pipe connection area as well.
7. 7

   Prepare new muffler
   Unbox new muffler and verify it matches the original configuration (dual inlet, correct outlet diameter and orientation). Apply a thin coat of anti-seize compound to all flange bolt threads. Position the new exhaust flange gasket on the inlet flange of the new muffler.
8. 8

   Install muffler and connect rear hanger
   Lift the new muffler into position between the frame rails. Align it roughly with the mounting points. Connect the rear-most hanger rod into its rubber isolator first to help support the muffler weight.
9. 9

   Connect middle and front hangers
   Work the middle hanger rod into its rubber isolator mount. Then connect the front hanger rod into its isolator. The muffler should now be supported by all three hangers. Adjust position as needed to align inlet and outlet connections.
10. 10

    Connect inlet flange
    Align the muffler inlet flange with the intermediate pipe flange, ensuring the new gasket is properly positioned between them. Start all flange bolts by hand to ensure proper thread engagement. Use a 15mm socket and torque wrench to tighten flange bolts to specification in a cross-pattern.
11. 11

    Connect outlet pipe
    Align the muffler outlet with the tailpipe connection. For clamp-type connections, position the clamp over the joint and start the clamp bolts. For flanged connections, install bolts with anti-seize. Tighten clamp bolts or flange bolts to specification using appropriate socket and torque wrench.
    Torque spec

    Muffler Clamps55 Nm (41 lb-ft)
12. 12

    Verify alignment and clearances
    Visually inspect the entire exhaust system from catalytic converters to tailpipe tip. Ensure no part of the exhaust is contacting the frame, body, fuel tank, fuel lines, brake lines, or suspension components. Verify at least 1 inch clearance to all components. Adjust hanger positions if needed to achieve proper clearance.

Reassembly

1. Double-check all fasteners are tightened to proper torque specifications
2. Verify all three rubber hanger isolators are properly engaged
3. Confirm exhaust system has adequate clearance from all chassis components, fuel system, and heat-sensitive parts
4. Remove jack stands and carefully lower vehicle to ground

Verification

• Start engine and allow to idle - listen for any exhaust leaks at the inlet flange and outlet connections (a hissing or ticking sound indicates a leak)
• With engine running, carefully feel around connections for escaping exhaust gases (do not touch hot components)
• Perform a short test drive and listen for any rattles, buzzes, or contact sounds that would indicate improper clearance or loose connections
• After test drive, re-check all fastener torques while exhaust is warm (but not hot)
• Perform final visual inspection under vehicle to confirm no contact points or clearance issues developed during test drive

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