This procedure covers removal and replacement of the downpipe assembly on the 5.0L Coyote V8 engine, connecting the exhaust manifolds to the catalytic converter section.

Warnings

Tools required

Parts

• Downpipe assembly × 1 — Use OEM specification or aftermarket equivalent
• Exhaust flange gaskets × 2 — Use OEM specification
• Exhaust hanger insulators (if worn) × 2 — Use OEM specification
• Oxygen sensor(s) (if replacing) × 2 — Motorcraft DY1508 or equivalent

Preparation

1. Park vehicle on level ground and apply parking brake
2. Place wheel chocks behind rear wheels
3. Allow exhaust system to cool completely (minimum 2 hours after engine operation)
4. Raise front of vehicle and secure on jack stands rated for vehicle weight
5. Spray all exhaust flange bolts, oxygen sensor threads, and hanger bolts with penetrating oil
6. Disconnect negative battery terminal to prevent oxygen sensor codes during removal
7. Remove engine splash shield and skid plates if equipped

Procedure

1. 1

   Disconnect oxygen sensors
   Locate the upstream oxygen sensors on both driver and passenger side downpipes. Disconnect the electrical connectors by pressing the tab and pulling firmly. Use the 22mm oxygen sensor socket to carefully remove both sensors from the downpipe. Work slowly to avoid breaking the sensor or stripping threads. Set sensors aside if reusing.
2. 2

   Remove heat shield fasteners
   Remove the heat shield covering the downpipe assembly using a 10mm socket. There are typically 4-6 bolts securing the shield to the undercarriage and transmission crossmember. Set heat shield aside. Note the position of any spacers or washers for reinstallation.
   Torque spec

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

   Disconnect exhaust hangers
   Locate the rubber exhaust hangers supporting the downpipe assembly. Use a pry bar or pull firmly by hand to separate the exhaust hanger rods from the rubber insulators. There are typically 2 hangers on the downpipe section. Inspect rubber insulators for cracking or deterioration and replace if necessary.
   Torque spec

   Hanger Bolts25 Nm (19 lb-ft)
4. 4

   Support downstream exhaust
   Position a floor jack with a block of wood under the catalytic converter section downstream of the downpipe. Raise just enough to support the weight without lifting the vehicle. This prevents the exhaust from falling and provides alignment assistance during reinstallation.
5. 5

   Remove downstream exhaust flange connection
   Locate the flange connection between the downpipe and the catalytic converter section. Remove the two flange bolts using a 15mm socket. The flange is a spring-loaded design, so support the connection as you remove the final bolt. Separate the flanges and slide the connection apart. Remove and discard the old gasket.
   Torque spec

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

   Remove driver side exhaust manifold connection
   Working from underneath, locate the flange connection between the driver side exhaust manifold and downpipe. Remove the two flange bolts using a 13mm socket. Work carefully as these bolts are prone to breaking. If a bolt breaks, note that stud extraction will be required before reinstallation. Remove and discard the old gasket.
   ⚠Exhaust manifold studs frequently seize and break. If a stud breaks, stop and extract the broken stud before proceeding.
   Torque spec

   Exhaust Flange Bolts45 Nm (33 lb-ft)
7. 7

   Remove passenger side exhaust manifold connection
   Locate the flange connection between the passenger side exhaust manifold and downpipe. Remove the two flange bolts using a 13mm socket. Apply steady pressure and avoid impact tools if possible to minimize risk of breaking studs. Remove and discard the old gasket.
   ⚠Exhaust manifold studs frequently seize and break. If a stud breaks, stop and extract the broken stud before proceeding.
   Torque spec

   Exhaust Flange Bolts45 Nm (33 lb-ft)
8. 8

   Remove downpipe assembly
   With all connections separated, carefully maneuver the downpipe assembly down and out from under the vehicle. The assembly will need to be rotated and angled to clear the transmission crossmember, steering components, and transfer case. Work slowly to avoid damaging brake lines or other components. The assembly weighs approximately 25-35 pounds.
9. 9

   Clean all flange surfaces
   Use a wire brush to thoroughly clean all flange mating surfaces on the exhaust manifolds and catalytic converter section. Remove all traces of old gasket material, carbon buildup, and rust. Clean surfaces ensure proper sealing and prevent exhaust leaks. Clean the oxygen sensor bungs if reusing sensors.
10. 10

    Install oxygen sensors in new downpipe
    Apply a small amount of anti-seize compound to the threads of both oxygen sensors. Do not allow anti-seize to contact the sensor tip. Thread sensors into the new downpipe by hand first, then tighten to specification using the 22mm oxygen sensor socket and torque wrench.
    ⚠Apply anti-seize to threads only. Contamination of the sensor tip will cause incorrect readings and engine performance issues.
    Torque spec

    O2 Sensor45 Nm (33 lb-ft)
11. 11

    Position new downpipe assembly
    Maneuver the new downpipe assembly into position under the vehicle, reversing the removal process. Support the assembly and align it with the exhaust manifold flanges first. Install new gaskets at all three flange connections (both manifolds and downstream connection). Use mechanics wire to temporarily hold the assembly in position if needed.
12. 12

    Connect to exhaust manifolds
    Install new gaskets at both exhaust manifold flanges. Apply anti-seize compound to the threads of the flange bolts. Start all four bolts (two per side) by hand to ensure proper alignment. Tighten the driver side flange bolts to specification, then tighten the passenger side flange bolts to specification using a torque wrench.
    Torque spec

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

    Connect downstream exhaust section
    Adjust the position of the jack supporting the catalytic converter section to align with the downpipe flange. Install a new gasket at the flange connection. Install both flange bolts and tighten to specification. Verify the connection is properly seated and aligned.
    Torque spec

    Exhaust Flange Bolts45 Nm (33 lb-ft)
14. 14

    Reinstall exhaust hangers and heat shield
    Reconnect the exhaust hanger rods to the rubber insulators. Ensure hangers are fully seated and the exhaust has proper clearance from the undercarriage and driveline components. Reinstall the heat shield and tighten all fasteners to specification.
    Torque spec

    Hanger Bolts25 Nm (19 lb-ft)

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

    Reconnect oxygen sensors and finalize
    Reconnect both oxygen sensor electrical connectors. Ensure connectors click into place and connections are secure. Reconnect the negative battery terminal. Reinstall any skid plates or splash shields removed during preparation. Remove jack stands and lower vehicle to the ground.

Reassembly

1. Double-check all flange connections are torqued to specification
2. Verify exhaust system has adequate clearance from frame, driveline, and brake lines throughout its length
3. Confirm all oxygen sensor electrical connections are secure and properly routed away from heat sources
4. Verify exhaust hangers are properly seated and not twisted or binding

Verification

• Start the engine and listen for exhaust leaks at all flange connections. A hissing sound indicates a leak requiring re-torquing or gasket replacement
• With engine running, check for excessive movement or vibration in the exhaust system
• Allow engine to reach operating temperature and verify no exhaust odor in cabin
• Use a scan tool to verify oxygen sensors are reading properly and no diagnostic trouble codes are present
• Test drive the vehicle and listen for rattles, vibrations, or exhaust contact with the undercarriage
• After 50-100 miles of driving, re-inspect all flange connections for signs of leakage or loosening

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