Exhaust Manifold

This procedure covers removal and replacement of one or both exhaust manifolds on the 3.5L EcoBoost V6 engine, including turbocharger access and related component removal.

Warnings

Tools required

Parts

• Exhaust manifold gasket(s) × 1 — Use OEM Ford specification
• Turbocharger to exhaust manifold gasket × 1 — Use OEM Ford specification
• Exhaust manifold nuts × 8 — Use OEM Ford fasteners
• Heat shield (if damaged) × 1 — Use OEM Ford specification
• Engine coolant × 2 — Motorcraft Orange Coolant

Fluids

• Motorcraft Orange Coolant — 2 qt

Preparation

1. Ensure engine is completely cool to the touch (minimum 2 hours after shutdown)
2. Disconnect negative battery cable and wait 5 minutes
3. Raise vehicle and support securely on jack stands
4. Remove engine splash shield/skid plate if equipped
5. Apply penetrating oil to all exhaust manifold nuts and O2 sensor threads, allow to soak
6. Drain approximately 2 quarts of coolant from radiator into drain pan to lower coolant level below turbocharger coolant lines

Procedure

1. 1

   Remove engine cover and air intake components
   Remove the plastic engine cover by pulling upward on the retention clips. Disconnect the air intake tube from the throttle body and remove the complete air filter housing assembly to access the turbocharger inlet. Label all vacuum lines and electrical connections before disconnecting.
   Torque spec

   Cover Bolts19 Nm (14 lb-ft)
2. 2

   Disconnect oxygen sensor(s)
   Locate the upstream oxygen sensor(s) on the exhaust manifold. Disconnect the electrical connector and use a 22mm O2 sensor socket to remove the sensor(s). Work carefully to avoid damaging the sensor threads in the manifold. If sensors are seized, apply additional penetrating oil and allow to soak.
   ⚠Do not force frozen O2 sensors. Broken sensors may require manifold removal to extract damaged threads.
   Torque spec

   O2 Sensor55 Nm (40 lb-ft)
3. 3

   Remove heat shield
   Remove the heat shield bolts securing the exhaust manifold heat shield. There are typically 3-4 bolts per shield. Keep track of any spacers or washers. The heat shield must be removed to access the manifold mounting nuts.
   Torque spec

   Heat Shield Bolts10 Nm (7 lb-ft)
4. 4

   Disconnect turbocharger coolant lines
   Locate the turbocharger coolant supply and return lines. Place a drain pan underneath and disconnect both lines at the turbocharger. Use a line wrench to prevent rounding off fittings. Cap or plug open lines to prevent contamination. Note routing and orientation for reinstallation.
   ⚠Coolant will drain from lines. Have drain pan positioned to catch approximately 1 quart of coolant.
5. 5

   Disconnect turbocharger oil feed and drain lines
   Disconnect the turbocharger oil feed line at the top of the turbocharger and the oil drain line at the bottom where it connects to the engine block. Use proper flare nut wrenches to avoid damaging fittings. Cap all open oil passages immediately to prevent contamination.
   ⚠Oil will drain from lines. Position drain pan to catch residual oil.
6. 6

   Disconnect exhaust downpipe from turbocharger
   From underneath the vehicle, locate the exhaust flange connection between the turbocharger outlet and the downpipe/catalytic converter. Remove the flange bolts securing this connection. You may need to support the exhaust system with a jack or hanger to prevent strain on other connections.
   ⚠Exhaust flange bolts are frequently seized. Apply additional penetrating oil and use a 6-point socket to minimize rounding.
   Torque spec

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

   Remove turbocharger-to-manifold connection (if separating)
   If replacing only the exhaust manifold and not the turbocharger, remove the bolts connecting the turbocharger to the exhaust manifold. If replacing the manifold and turbocharger as an assembly, skip this step and proceed to manifold removal with turbo attached.
   Torque spec

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

   Remove exhaust manifold mounting nuts
   Remove all exhaust manifold mounting nuts in reverse of the tightening sequence (working from cold end toward hot end/center cylinders). There are typically 8 nuts per manifold on the 3.5L EcoBoost. Work slowly and evenly to prevent warping. If a stud breaks, mark its location for extraction after manifold removal.
   ⚠Broken studs are common on this engine. If a stud breaks, you may need to remove the cylinder head or use a stud extractor.
   Torque spec

   Exhaust Manifold Nuts30 Nm (22 lb-ft)
9. 9

   Remove exhaust manifold assembly
   Carefully separate the exhaust manifold from the cylinder head. You may need to gently pry between the manifold and head using a gasket scraper or pry bar, being careful not to damage the sealing surface on the head. Maneuver the manifold/turbo assembly out of the engine bay, noting any tight clearances for reinstallation.
   ⚠Manifold assembly with turbocharger is heavy and awkward. Use a second person or support device to prevent dropping.
10. 10

    Clean mating surfaces
    Thoroughly clean all gasket material from the cylinder head mating surface using a gasket scraper. Do not gouge or damage the head surface. Clean the manifold mating surface as well if reusing. Inspect the head surface for warping or damage. If studs were broken, extract them now using a stud extractor or drill and easy-out, then install new studs.
    ℹ️Do not allow debris to fall into cylinder head ports. Stuff clean rags into ports during cleaning.
11. 11

    Install new exhaust manifold
    Position the new exhaust manifold gasket on the cylinder head studs. Apply a small amount of anti-seize to the stud threads (avoid getting anti-seize on gasket surfaces). Carefully position the new or cleaned exhaust manifold onto the studs. Start all nuts by hand to ensure proper alignment before tightening.
    Torque spec

    Exhaust Manifold Nuts30 Nm (22 lb-ft)
12. 12

    Torque exhaust manifold nuts to specification
    Using a torque wrench, tighten the exhaust manifold nuts to 30 Nm (22 lb-ft) in the proper sequence, working from the hot center cylinders toward the cold outer ends. Tighten in multiple passes: first pass to 50% torque, second pass to 100% torque. Verify tightening sequence in factory service manual as improper sequence can cause manifold warping.
    ⚠Always verify tightening sequence with service manual. Incorrect sequence can warp manifold and cause exhaust leaks.
    Torque spec

    Exhaust Manifold Nuts30 Nm (22 lb-ft)
13. 13

    Reconnect turbocharger to manifold or exhaust
    If turbocharger was separated from manifold, install new gasket and reconnect using flange bolts torqued to specification with anti-seize applied. If turbo remained attached to manifold, proceed to reconnect the exhaust downpipe to the turbocharger outlet with new gasket.
    Torque spec

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

    Reconnect turbocharger oil and coolant lines
    Reconnect the turbocharger oil feed line at the top and oil drain line at the bottom. Torque fittings per specification. Reconnect coolant supply and return lines, ensuring proper routing and no kinks. Replace any damaged O-rings or seals with new OEM parts.
    ℹ️Double-check all oil and coolant connections are tight before refilling fluids.
15. 15

    Install heat shield and oxygen sensors
    Reinstall the exhaust manifold heat shield and torque bolts to specification per service manual sequence. Apply anti-seize compound to oxygen sensor threads and install sensors, torquing to 55 Nm (40 lb-ft). Reconnect O2 sensor electrical connectors.
    Torque spec

    Heat Shield Bolts10 Nm (7 lb-ft)

    O2 Sensor55 Nm (40 lb-ft)

Reassembly

1. Reinstall air intake system and engine cover, torquing cover bolts to 19 Nm (14 lb-ft)
2. Refill cooling system with Motorcraft Orange Coolant to proper level (approximately 2 quarts)
3. Check engine oil level and top off if necessary due to turbo oil line drainage
4. Reinstall engine splash shield/skid plate if equipped
5. Lower vehicle from jack stands
6. Reconnect negative battery cable

Verification

• Bleed cooling system by running engine to operating temperature with heater on high, then topping off coolant when cool
• Use a cooling system pressure tester to verify no coolant leaks at turbocharger connections
• Start engine and listen for exhaust leaks at manifold-to-head interface and all flange connections
• Check for oil leaks at turbocharger oil feed and drain lines after 5 minutes of operation
• Verify no coolant or oil drips underneath vehicle after first test drive
• Perform a test drive and verify normal turbocharger boost operation and no unusual exhaust noises
• Re-check all torque specifications after engine has fully cooled from first heat cycle
• Scan for diagnostic trouble codes to ensure all oxygen sensors are functioning properly

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