Intake Manifold Gasket

This procedure covers removal and replacement of the intake manifold gaskets on the 3.5L EcoBoost V6 engine, including throttle body, fuel rail, and sensor removal.

Warnings

Tools required

Parts

• Intake manifold gasket set (upper and lower) × 1 — Use OEM specification
• Throttle body gasket × 1 — Use OEM specification
• PCV valve grommet × 1 — Use OEM specification
• Fuel injector O-rings (if damaged) × 6 — Use OEM specification

Fluids

• Motorcraft Orange Coolant — 2 qt

Preparation

1. Ensure engine is completely cool to the touch
2. Disconnect negative battery cable and wait 10 minutes for system capacitors to discharge
3. Remove engine cover by pulling upward on integrated pull points
4. Drain cooling system by opening radiator petcock and lower radiator hose until level drops below intake manifold
5. Relieve fuel system pressure by removing fuel pump fuse and cranking engine until it stalls, then crank 5 more seconds
6. Place clean towels around fuel rail area to catch residual fuel
7. Label all electrical connectors, vacuum lines, and hoses with tape and marker for reassembly reference

Procedure

1. 1

   Remove air intake system
   Disconnect mass airflow sensor electrical connector. Loosen clamps on air intake tube at throttle body and air filter housing. Remove entire air intake tube assembly. Remove air filter housing if needed for access by disconnecting mounting bolts and any breather hoses.
2. 2

   Disconnect throttle body and vacuum connections
   Disconnect throttle body electrical connector. Disconnect vacuum lines from intake manifold, noting routing: brake booster vacuum line, PCV hose, EVAP purge line, and any other vacuum-operated accessories. Use pick tool if hoses are stubborn. Remove throttle body mounting bolts and set throttle body aside with coolant hoses still attached if possible.
   ℹ️Throttle body coolant hoses can remain connected if adequate slack exists; otherwise drain and disconnect.
   Torque spec

   Throttle Body Bolts10 Nm (7 lb-ft)
3. 3

   Remove electrical connections and sensors
   Disconnect all electrical connectors from intake manifold including: fuel injector harness connectors (6), manifold absolute pressure sensor, intake air temperature sensor, and any other sensors mounted to manifold. Press release tabs and pull connectors straight out. Remove sensor mounting bolts for any sensors that must be removed from manifold.
4. 4

   Disconnect fuel system
   Using appropriate fuel line disconnect tools, disconnect fuel supply line from fuel rail. Have shop towels ready to catch fuel spillage. Disconnect fuel rail electrical connectors if not already done. Remove fuel rail mounting bolts and carefully lift fuel rail with injectors attached straight up and out of intake manifold. Cap or plug fuel line opening immediately.
   ⚠️Fuel will spill from lines and rail. Keep away from ignition sources and have fire extinguisher accessible.
   Torque spec

   Fuel Rail Bolts12 Nm (9 lb-ft)
5. 5

   Remove PCV valve and EGR components
   Remove PCV valve from valve cover by twisting and pulling. If equipped with EGR, disconnect EGR valve electrical connector and coolant lines. Remove EGR valve mounting bolts and remove valve with gasket. Plug coolant openings if coolant lines were disconnected.
   ℹ️Some production dates may not include EGR valve; verify before attempting removal.
6. 6

   Disconnect coolant crossover and remaining hoses
   If equipped with coolant crossover pipe on intake manifold, remove mounting bolts and disconnect coolant hoses. Remove any remaining coolant hoses, heater hoses, or vapor purge connections attached to intake manifold. Keep track of all hardware.
7. 7

   Remove intake manifold
   Remove intake manifold mounting bolts in reverse order of tightening sequence (outside to center pattern). There are typically 8-10 bolts securing the manifold. Carefully lift intake manifold straight up to avoid damaging gasket surfaces on cylinder heads. If manifold is stuck, gently pry at designated pry points only—never between gasket surfaces.
   ⚠Do not pry between manifold and cylinder head gasket surfaces as this will cause damage requiring resurfacing.
   Torque spec

   Intake Manifold Bolts25 Nm (18 lb-ft)
8. 8

   Remove old gaskets and clean surfaces
   Remove all old gasket material from intake manifold mating surface and cylinder head surfaces using plastic scraper only. Never use metal scrapers on aluminum surfaces. Clean all surfaces thoroughly with brake cleaner and lint-free shop towels. Inspect surfaces for damage, warping, or deep scratches. Ensure all bolt holes are clean and free of debris or coolant.
   ⚠Metal scrapers will gouge aluminum surfaces. Use only plastic scrapers and chemical gasket removers if needed.
   ℹ️Cover open intake ports on cylinder heads with clean towels to prevent debris from entering engine.
9. 9

   Install new gaskets and position intake manifold
   Install new intake manifold gaskets on cylinder heads, ensuring alignment pins or tabs are properly seated. Do not use gasket sealant unless specifically required by gasket manufacturer. Carefully lower intake manifold into position, aligning all bolt holes and ensuring gaskets remain properly positioned. Visually verify gasket alignment before installing bolts.
10. 10

    Install and torque intake manifold bolts
    Install all intake manifold bolts hand-tight first. Using torque wrench, tighten bolts to 25 Nm (18 lb-ft) in proper sequence from center outward in a crisscross pattern. Make at least two complete passes through the sequence to ensure even gasket compression. Verify all bolts reach specified torque.
    ⚠Follow center-out tightening sequence precisely. Uneven tightening will warp manifold and cause vacuum leaks.
    Torque spec

    Intake Manifold Bolts25 Nm (18 lb-ft)
11. 11

    Reinstall fuel rail and injectors
    Inspect fuel injector O-rings for damage and replace if necessary. Lubricate O-rings with clean engine oil. Carefully press fuel rail with injectors into intake manifold bores, ensuring all injectors seat properly. Install fuel rail mounting bolts and torque to 12 Nm (9 lb-ft). Reconnect fuel supply line and all fuel injector electrical connectors.
    Torque spec

    Fuel Rail Bolts12 Nm (9 lb-ft)
12. 12

    Reinstall PCV valve, EGR, and coolant components
    Install new PCV valve grommet in valve cover if removed. Install PCV valve and torque to 8 Nm (6 lb-ft). If equipped with EGR, install new EGR gasket, position EGR valve, and torque bolts to 25 Nm (18 lb-ft). Reconnect EGR electrical connector and coolant lines. Reinstall coolant crossover if equipped and torque bolts to 15 Nm (11 lb-ft).
13. 13

    Reinstall throttle body and sensors
    Install new throttle body gasket. Position throttle body and install mounting bolts, torquing to 10 Nm (7 lb-ft). Reconnect throttle body electrical connector. Reinstall any sensors removed from intake manifold, torquing sensor mounting bolts to 12 Nm (9 lb-ft) and electrical connector bolts to 8 Nm (6 lb-ft).
    Torque spec

    Throttle Body Bolts10 Nm (7 lb-ft)
14. 14

    Reconnect vacuum lines and air intake
    Reconnect all vacuum lines to intake manifold in original positions using reference labels: brake booster, EVAP purge, PCV, and any auxiliary vacuum lines. Ensure all connections are secure. Reinstall air filter housing if removed. Install air intake tube and tighten clamps at throttle body and air filter housing. Reconnect mass airflow sensor electrical connector.
15. 15

    Refill coolant and final connections
    Close radiator petcock and reconnect any coolant hoses. Refill cooling system with Motorcraft Orange Coolant to proper level. Reconnect negative battery cable. Remove all tools and towels from engine compartment. Install engine cover by aligning grommets and pressing down firmly until seated.

Reassembly

1. Double-check all electrical connectors are firmly seated with locking tabs engaged
2. Verify all vacuum lines are connected and properly routed without kinks
3. Ensure fuel line connection is secure and properly locked
4. Confirm no tools or hardware remain in engine compartment

Verification

• Start engine and allow to idle. Listen for vacuum leaks (hissing sounds) around intake manifold perimeter
• Check for fuel leaks around fuel rail and supply line connections while engine is running
• Monitor coolant level and check for leaks around coolant crossover and EGR connections if equipped
• Verify engine runs smoothly with no rough idle, misfires, or check engine light
• Test drive vehicle and verify normal acceleration and throttle response without hesitation
• After first drive cycle, recheck coolant level when engine is cool and top off if necessary
• Scan for diagnostic trouble codes using OBD-II scanner to confirm no fuel trim, misfire, or vacuum leak codes are present

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