This procedure covers removal and installation of the intake manifold on a 2021-2024 Ford F-150 with the 3.5L EcoBoost V6 engine, including upper and lower manifold components.

Warnings

Tools required

Parts

• Lower intake manifold gaskets × 2 — Use OEM Ford gaskets
• Upper intake manifold gasket × 1 — Use OEM Ford gasket
• Throttle body gasket × 1 — Use OEM specification
• PCV valve grommet (if damaged) × 1 — Inspect and replace as needed
• Fuel injector O-rings (if disturbed) × 6 — Use OEM specification

Fluids

• Motorcraft Orange Coolant — 2 qt

Preparation

1. Ensure engine is completely cold (allow at least 2 hours after running)
2. Disconnect negative battery cable and wait 5 minutes for system capacitors to discharge
3. Remove engine cover by pulling upward on front clips and lifting off
4. Relieve fuel system pressure: Remove fuel pump fuse, start engine and let it run until it stalls, then crank for 5 seconds to ensure complete pressure relief
5. Drain cooling system: Open radiator petcock and drain approximately 2 quarts of coolant into drain pan
6. Position catch pans under work area to capture any residual coolant or fuel
7. Label all electrical connectors and vacuum lines with tape for identification during reassembly

Procedure

1. 1

   Remove air intake system
   Disconnect mass airflow sensor electrical connector. Loosen clamp at throttle body and turbocharger inlet. Remove complete air intake tube assembly from engine bay. Remove air filter housing if needed for additional clearance.
2. 2

   Disconnect throttle body and PCV connections
   Disconnect throttle body electrical connector. Disconnect PCV hose from valve cover and upper intake manifold. Remove any vacuum lines connected to upper intake manifold, noting routing for reassembly.
3. 3

   Remove throttle body
   Remove four throttle body mounting bolts. Carefully pull throttle body away from upper intake manifold. Remove and discard throttle body gasket. Cover throttle body opening with clean shop towel to prevent debris entry.
   Torque spec

   Throttle Body Bolts10 Nm (7 lb-ft)
4. 4

   Disconnect brake booster and EVAP lines
   Disconnect brake booster vacuum line from upper intake manifold. Disconnect EVAP purge line if equipped. Remove any remaining vacuum lines or breather hoses from upper manifold assembly.
5. 5

   Remove upper intake manifold
   Remove electrical connectors for any sensors mounted to upper manifold (MAP sensor, charge air cooler temperature sensor if equipped). Remove upper intake manifold bolts in reverse of tightening sequence (outside to center pattern). Carefully lift upper intake manifold away from lower manifold. Remove and discard upper intake gasket.
   ℹ️Upper intake manifold bolts are torqued in INCH-POUNDS (89 in-lb), not foot-pounds. Note the tightening sequence for reassembly.
   Torque spec

   Intake Manifold Bolts25 Nm (18 lb-ft)
6. 6

   Disconnect fuel system
   Verify fuel pressure is relieved. Use fuel line disconnect tool to separate fuel supply line from fuel rail. Have shop towels ready to catch residual fuel. Cap or plug fuel line to prevent contamination. Disconnect fuel injector electrical connectors on both banks.
   ⚠Even after pressure relief, residual fuel will spill. Keep ignition sources away and work in well-ventilated area.
7. 7

   Remove fuel rails
   Remove fuel rail mounting bolts from both left and right fuel rails. Carefully pull fuel rails with injectors still attached straight up and away from lower intake manifold. Place fuel rails in safe location away from work area. Cap or cover injector ports in manifold to prevent debris entry.
   ℹ️Fuel rail bolts have specific tightening sequence. Verify sequence in service manual before reassembly.
   Torque spec

   Fuel Rail Bolts12 Nm (9 lb-ft)
8. 8

   Disconnect remaining sensors and hoses
   Disconnect coolant hoses from lower intake manifold (coolant crossover tube connections). Disconnect any remaining electrical connectors including coolant temperature sensors. Remove PCV valve if attached to lower manifold.
   Torque spec

   PCV Valve8 Nm (6 lb-ft)

   Mounting Bolts54 Nm (40 lb-ft)
9. 9

   Remove lower intake manifold
   Remove all lower intake manifold mounting bolts in reverse of tightening sequence (outside to center). Note that there are multiple bolts per side. Carefully lift lower intake manifold assembly straight up to clear cylinder heads. Inspect for any remaining connections before fully removing.
   ⚠Lower intake manifold is heavy and awkward. Use care when lifting to avoid dropping or damaging gasket surfaces.
   Torque spec

   Intake Manifold Bolts25 Nm (18 lb-ft)
10. 10

    Clean gasket surfaces
    Remove all old gasket material from cylinder head mating surfaces using plastic gasket scraper. Do not use metal scrapers that could gouge aluminum surfaces. Clean surfaces thoroughly with brake cleaner or approved gasket surface cleaner. Wipe dry with clean, lint-free towels. Inspect for any damage, cracks, or warping.
    ⚠Ensure no gasket material or debris falls into cylinder head ports or valleys. Cover openings if necessary during cleaning.
    Torque spec

    Gasket Surface Bolts23 Nm (17 lb-ft)
11. 11

    Install new lower intake gaskets and manifold
    Position new lower intake manifold gaskets on cylinder heads. Ensure gaskets are properly aligned with all ports and bolt holes. Carefully lower intake manifold into position, aligning with gaskets and dowel pins. Start all lower intake manifold bolts by hand before tightening.
12. 12

    Torque lower intake manifold
    Tighten lower intake manifold bolts to 25 Nm (18 lb-ft) following factory tightening sequence (center out pattern). Verify proper sequence in service manual. Use multiple passes, tightening in progressive steps to avoid gasket distortion.
    ⚠Proper torque sequence is critical to prevent vacuum leaks and ensure even gasket compression. Start from center and work outward.
    Torque spec

    Intake Manifold Bolts25 Nm (18 lb-ft)
13. 13

    Reinstall fuel rails and sensors
    Install new fuel injector O-rings if injectors were removed. Lubricate O-rings with clean engine oil. Carefully press fuel rails with injectors into lower intake manifold, ensuring all injectors seat properly. Install fuel rail bolts and tighten to 12 Nm (9 lb-ft) following proper sequence. Reconnect fuel injector electrical connectors. Install coolant temperature sensors and other sensors removed earlier, torquing to 12 Nm (9 lb-ft).
    Torque spec

    Fuel Rail Bolts12 Nm (9 lb-ft)

    Mounting Bolts54 Nm (40 lb-ft)
14. 14

    Install upper intake manifold
    Position new upper intake manifold gasket on lower manifold. Align upper intake manifold with gasket and carefully lower into place. Install all upper manifold bolts by hand. Tighten upper intake manifold bolts to 10 Nm (89 in-lb) following proper tightening sequence (consult service manual). Reconnect all sensors to upper manifold.
    ⚠Upper manifold bolts are torqued to 89 INCH-POUNDS, not foot-pounds. Using foot-pound torque wrench will result in overtightening and damage.
    Torque spec

    Intake Manifold Bolts25 Nm (18 lb-ft)
15. 15

    Reinstall throttle body and complete assembly
    Install new throttle body gasket. Position throttle body on upper intake manifold. Install and tighten throttle body bolts to 10 Nm (7 lb-ft) following proper sequence. Reconnect throttle body electrical connector. Reconnect PCV valve (torque to 8 Nm/6 lb-ft if threaded). Reconnect all vacuum lines, brake booster line, EVAP lines, and coolant hoses to proper locations using photos taken during disassembly. Reconnect fuel supply line to fuel rail until it clicks into place.
    Torque spec

    Throttle Body Bolts10 Nm (7 lb-ft)

    PCV Valve8 Nm (6 lb-ft)
16. 16

    Reinstall air intake system
    Install air intake tube to throttle body and turbocharger inlet. Tighten clamps securely. Reconnect mass airflow sensor electrical connector. Reinstall air filter housing if removed. Install engine cover by aligning clips and pressing down firmly until seated.

Reassembly

1. Refill cooling system with Motorcraft Orange Coolant to proper level (may need up to 2 quarts)
2. Reconnect negative battery cable
3. Reinstall fuel pump fuse
4. Before starting engine, turn ignition to ON position (without starting) 3-4 times to prime fuel system and check for fuel leaks
5. Bleed cooling system by running engine to operating temperature with heater on high, then topping off coolant as needed
6. Check all connections for proper seating and torque specifications

Verification

• Start engine and allow to idle. Listen for any vacuum leaks (hissing sounds) around intake manifold
• Check for fuel leaks at fuel rail connections and fuel supply line
• Check for coolant leaks at intake manifold coolant connections
• Verify throttle response is smooth and engine returns to proper idle
• Test brake booster function - brake pedal should feel firm with engine running
• Use scan tool to check for any diagnostic trouble codes related to fuel trim, MAF sensor, or intake air system
• Road test vehicle to verify proper engine performance, smooth acceleration, and no check engine light
• Recheck coolant level after test drive and top off if necessary
• Inspect for any fluid leaks after test drive while engine is at operating temperature

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