Intake Manifold Gasket

This procedure covers the removal and replacement of the intake manifold gasket on the 2018-2024 Honda Accord 1.5L turbocharged engine, including removal of associated components and proper torque sequence during reassembly.

Warnings

Tools required

Parts

• Intake manifold gasket × 1 — Use Honda OEM gasket
• Throttle body gasket × 1 — Use Honda OEM gasket
• PCV valve O-ring × 1 — Replace if damaged
• Coolant crossover O-rings × 1 — Replace if equipped and damaged

Fluids

• Honda Type 2 Coolant (Blue) — 1.5 qt

Preparation

1. Ensure engine is completely cool to the touch (minimum 2 hours after last operation)
2. Disconnect negative battery terminal and wait 3 minutes for airbag system to discharge
3. Remove engine cover by pulling upward on all four corners
4. Position drain pan under radiator and drain coolant from petcock until level is below intake manifold height
5. Relieve fuel system pressure by removing fuel pump fuse and cranking engine until it stalls, then crank 2-3 more times
6. Document all electrical connector positions, vacuum line routing, and breather hose locations with photos

Procedure

1. 1

   Remove air intake system
   Disconnect the mass airflow sensor electrical connector. Loosen the air intake duct clamp at the throttle body. Remove the air box mounting bolts and carefully lift the entire air intake assembly away from the engine bay. Disconnect any breather hoses attached to the air box.
2. 2

   Disconnect throttle body and associated components
   Disconnect the throttle body electrical connector. Remove the throttle body coolant hoses by releasing the spring clamps (catch any coolant spillage). Label or photograph vacuum hoses connected to the throttle body and intake manifold before disconnecting.
   ⚠Residual coolant will drain from throttle body coolant lines. Have rags ready to catch spillage.
3. 3

   Remove throttle body
   Remove the four throttle body mounting bolts. Carefully pull the throttle body away from the intake manifold. Inspect the throttle body gasket and replace if torn or damaged. Cover the intake manifold opening with a clean rag to prevent debris entry.
   Torque spec

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

   Disconnect fuel system components
   Using the appropriate fuel line disconnect tool, separate the fuel feed line from the fuel rail. Place rags beneath the connection to catch residual fuel. Disconnect the fuel injector harness connectors as a group by releasing the locking tab. Remove the fuel rail mounting bolts and carefully lift the fuel rail with injectors attached away from the manifold. Secure the fuel rail assembly out of the way without stressing fuel lines.
   ⚠️Even with pressure relieved, fuel will spill from disconnected lines. 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 the PCV valve by rotating counterclockwise and pulling from the valve cover grommet. If equipped with EGR valve, disconnect the EGR valve electrical connector, remove EGR valve bolts, and separate the EGR valve from the intake manifold. Cap or cover all openings.
6. 6

   Disconnect remaining sensors and hoses
   Disconnect the manifold absolute pressure (MAP) sensor electrical connector. Disconnect all remaining vacuum hoses from the intake manifold, labeling each connection. Disconnect any breather hoses attached to the intake manifold or valve cover. If equipped, disconnect the coolant crossover line from the intake manifold.
7. 7

   Remove intake manifold support brackets
   Locate and remove any support brackets or braces connecting the intake manifold to the cylinder head or engine block. These mounting bolts secure structural supports that must be removed before the manifold can be lifted away.
8. 8

   Remove intake manifold bolts
   Remove the intake manifold mounting bolts in reverse order of the tightening sequence (working from outside toward center). Keep bolts organized by location. Once all bolts are removed, gently work the intake manifold upward and away from the cylinder head. The manifold may be stuck to the gasket; gently rock it to break the seal, but do not pry against sealing surfaces.
   ⚠Do not pry between the manifold and cylinder head as this will damage sealing surfaces and cause permanent vacuum leaks.
   Torque spec

   Intake Manifold Bolts25 Nm (18 lb-ft)
9. 9

   Remove old gasket and clean surfaces
   Carefully remove the old intake manifold gasket from both the cylinder head and manifold surfaces. Use a plastic gasket scraper to remove all old gasket material without scratching the aluminum surfaces. Clean both mating surfaces thoroughly with brake cleaner and lint-free rags. Use a shop vacuum to remove any debris from the intake ports. Inspect surfaces for damage, warping, or deep scratches that could prevent proper sealing.
   ⚠Cover intake ports with clean rags during cleaning to prevent debris from entering the cylinders. Any debris in cylinders can cause severe engine damage.
10. 10

    Install new gasket and position intake manifold
    Place the new intake manifold gasket on the cylinder head, ensuring proper alignment with all intake ports and bolt holes. The gasket should fit precisely without forcing. Carefully lower the intake manifold onto the gasket, aligning all bolt holes. Install all intake manifold bolts hand-tight initially to ensure proper alignment before final torquing.
    ℹ️Verify gasket orientation matches the old gasket. Some gaskets have a specific up/down orientation marked with 'TOP' or directional arrows.
11. 11

    Torque intake manifold bolts
    Using a torque wrench, tighten the intake manifold bolts to specification in the proper sequence, starting from the center bolts and working outward in a spiral pattern. Make multiple passes, first to 50% torque, then to full specification, following the same sequence each time to ensure even gasket compression.
    ⚠Proper bolt sequence is critical. Incorrect tightening pattern will cause vacuum leaks and potential gasket failure.
    Torque spec

    Intake Manifold Bolts25 Nm (18 lb-ft)
12. 12

    Reinstall support brackets and coolant components
    Reinstall any intake manifold support brackets and braces, torquing mounting bolts to specification. If equipped, install coolant crossover line with new O-rings and torque coolant crossover bolts to specification. Ensure all connections are secure.
13. 13

    Reinstall PCV valve and EGR components
    Install PCV valve into valve cover grommet with new O-ring if needed, torquing to specification. If equipped, install EGR valve with new gasket, torque EGR valve bolts to specification, and reconnect electrical connector.
14. 14

    Reinstall fuel rail and injectors
    Carefully position the fuel rail and injector assembly over the intake manifold, ensuring all injectors align properly with their ports. Install fuel rail bolts and torque to specification. Reconnect the fuel injector harness connector. Connect the fuel feed line, ensuring it clicks securely into place.
    Torque spec

    Fuel Rail Bolts12 Nm (9 lb-ft)
15. 15

    Reinstall throttle body and remaining components
    Install throttle body with new gasket, torquing throttle body bolts to specification in a cross pattern. Reconnect throttle body coolant hoses with spring clamps. Reconnect throttle body electrical connector. Reconnect all vacuum hoses, breather hoses, and MAP sensor connector according to documentation taken during disassembly. Install air intake system and reconnect mass airflow sensor.
    Torque spec

    Throttle Body Bolts10 Nm (7 lb-ft)

Reassembly

1. Refill cooling system with Honda Type 2 Coolant to proper level, burping air from system using bleeder screw if equipped
2. Reinstall engine cover by pressing firmly at all mounting points until clips engage
3. Reconnect negative battery terminal and tighten securely
4. Reinstall fuel pump fuse to restore fuel system operation

Verification

• Turn ignition to ON position (without starting) and listen for fuel pump priming. Check for fuel leaks around fuel rail connections
• Start engine and allow to idle. Check for vacuum leaks by listening for hissing sounds around intake manifold perimeter and all vacuum connections
• Monitor for coolant leaks at throttle body and coolant crossover connections while engine warms up
• Verify smooth idle and throttle response with no hesitation or rough running
• Check for diagnostic trouble codes using OBD-II scanner. Address any codes related to air/fuel mixture, MAP sensor, or throttle body
• Road test vehicle under light and moderate acceleration to verify proper engine performance and boost pressure (if equipped with boost gauge)
• After test drive, recheck all connections and fluid levels. Inspect for any signs of leaks with engine at operating temperature

Related trouble codes on this vehicle

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