Exhaust Pipe - Rear Section

This procedure covers the removal and replacement of the rear exhaust pipe section on a 2015-2020 Ford F-150 with the 3.5L EcoBoost V6 engine, from the connection point behind the catalytic converters to the muffler outlet.

Warnings

Tools required

Parts

• Rear exhaust pipe assembly × 1 — Use OEM specification or aftermarket equivalent
• Exhaust flange gasket × 1 — Use OEM specification
• Exhaust hanger insulators × 2 — Replace if damaged

Preparation

1. Park vehicle on level surface and apply parking brake
2. Place wheel chocks behind front wheels
3. Allow exhaust system to cool completely (minimum 1 hour after engine shutdown)
4. Apply penetrating oil to all exhaust flange bolts, hanger bolts, and heat shield bolts
5. Raise rear of vehicle and support securely on jack stands at frame rails
6. Perform visual inspection of exhaust routing and component locations

Procedure

1. 1

   Disconnect oxygen sensor(s)
   Locate the oxygen sensor(s) on the rear exhaust section. Trace the wiring harness and disconnect the electrical connector(s) by pressing the release tab. If removing the sensor(s) from the old pipe for reuse, use a 22mm oxygen sensor socket to carefully unthread the sensor(s) counterclockwise. Set aside for reinstallation.
2. 2

   Remove heat shield bolts
   If equipped with exhaust heat shields in the rear section area, remove the heat shield mounting bolts using a 13mm socket. Keep track of bolt locations as some may be different lengths. Remove heat shields and set aside.
   Torque spec

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

   Support rear exhaust section
   Position a floor jack or exhaust support stand under the muffler to support the weight of the rear exhaust section. Raise slightly to take tension off the hangers and flange connection. This prevents the pipe from falling when disconnected.
   ⚠Ensure adequate support is in place before disconnecting exhaust components to prevent sudden dropping or pinching hazards.
4. 4

   Remove exhaust hanger bolts
   Locate the rubber hanger insulators that support the rear exhaust section (typically 2 hangers). Remove the hanger mounting bolts using a 15mm socket. If the rubber insulators are cracked or deteriorated, remove them from the exhaust hangers for replacement.
   Torque spec

   Hanger Bolts23 Nm (17 lb-ft)
5. 5

   Remove front flange connection bolts
   At the front connection point where the rear section connects to the mid-pipe or catalytic converter outlet, spray additional penetrating oil on the flange bolts. Using an 18mm socket, remove the flange bolts (typically 2 bolts). These may be heavily corroded and require significant force. If bolts break or strip, use a bolt extractor or cut with an angle grinder.
   ⚠Corroded flange bolts may break during removal. Have replacement bolts available if originals are damaged.
   Torque spec

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

   Separate flange connection
   With bolts removed, carefully pry the flange connection apart using a pry bar. The old gasket may be stuck and require gentle persuasion. Once separated, lower the support jack slightly and maneuver the rear exhaust section to clear the connection point.
7. 7

   Remove rear exhaust section
   With all connections and hangers disconnected, carefully lower and remove the rear exhaust section from under the vehicle. Maneuver around the rear axle and driveshaft as needed. Handle carefully to avoid damaging brake lines or fuel lines.
8. 8

   Clean flange mating surface
   Using a wire brush and gasket scraper, thoroughly clean the flange mating surface on the mid-pipe where the new rear section will connect. Remove all old gasket material, rust, and debris. The surface must be clean and flat for proper sealing.
9. 9

   Install oxygen sensor(s) in new pipe
   If reusing oxygen sensors, apply a small amount of anti-seize compound to the sensor threads only (avoid getting anti-seize on the sensor tip). Thread sensors into the new rear exhaust section by hand, then tighten using the oxygen sensor socket and torque wrench.
   ⚠Do not apply anti-seize to oxygen sensor tip or contaminate the sensing element. Apply only to threads.
   Torque spec

   O2 Sensor45 Nm (33 lb-ft)
10. 10

    Position new rear exhaust section
    Maneuver the new rear exhaust section into position under the vehicle, routing around the rear axle and driveshaft. Support with the floor jack. Install new rubber hanger insulators onto the exhaust hangers if replacements are needed. Align the exhaust hangers with the chassis mounting points.
11. 11

    Install new flange gasket and align connection
    Place the new exhaust flange gasket onto the mid-pipe flange. Raise the rear section with the support jack to align the flanges together. Ensure proper alignment before inserting bolts. The gasket should be centered between the flanges.
12. 12

    Install and torque flange bolts
    Apply anti-seize compound to the threads of the flange bolts. Insert bolts through the flange and thread by hand. Once both bolts are started, tighten in a cross pattern. Use a torque wrench to tighten flange bolts to specification. Do not fully tighten hangers yet to allow for alignment adjustment.
    Torque spec

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

    Install and torque hanger bolts
    With the flange connection secure, adjust the position of the rear exhaust section to ensure proper clearance from the chassis, fuel tank, and rear axle (minimum 1 inch clearance recommended). Once positioned correctly, install and torque the hanger mounting bolts.
    Torque spec

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

    Reinstall heat shields
    If heat shields were removed, reposition them over the exhaust components. Install and torque the heat shield bolts to specification. Ensure shields are properly seated and not rattling against exhaust or chassis components.
    Torque spec

    Heat Shield Bolts10 Nm (7 lb-ft)
15. 15

    Reconnect oxygen sensor connectors
    Reconnect the oxygen sensor electrical connector(s) by pressing firmly until the locking tab clicks into place. Ensure wiring is routed away from hot exhaust components and is secured with any factory clips or ties. Verify connectors are fully seated.

Reassembly

1. Double-check all fasteners are torqued to specification
2. Verify minimum 1 inch clearance between exhaust and all chassis components, fuel lines, and brake lines
3. Ensure oxygen sensor wiring is properly routed and secured
4. Remove jack stands and lower vehicle to ground

Verification

• Start engine and allow to idle. Listen for exhaust leaks at the flange connection (hissing or ticking sounds indicate a leak)
• Perform visual inspection under vehicle while engine is running to check for visible exhaust leaks
• Rev engine to 2000-2500 RPM and listen for unusual rattles or contact noises indicating improper clearance
• Check for any exhaust odors in cabin which would indicate a leak in the system
• Take a short test drive and verify normal exhaust sound with no vibrations or rattles
• After test drive, recheck all fasteners for proper torque and inspect for any signs of exhaust soot indicating leaks

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