This procedure covers removal and replacement of the intake manifold on the 2014-2019 Toyota Corolla 1.8L I4 engine, including disconnection of fuel, vacuum, and electrical components.

Warnings

Tools required

Parts

• Intake manifold gasket × 1 — Use OEM specification
• Throttle body gasket × 1 — Use OEM specification
• PCV valve (if damaged) × 1 — Use OEM specification
• Vacuum hoses (if cracked) × 1 — Use OEM specification

Fluids

• Toyota Super Long Life Coolant (Pink) — 1.5 qt

Preparation

1. Ensure engine is completely cool to the touch
2. Park vehicle on level surface and engage parking brake
3. Disconnect negative battery terminal and wait 90 seconds
4. Remove engine cover by pulling upward on the cover (friction fit)
5. Relieve fuel system pressure by removing fuel pump relay and cranking engine until it stalls, then crank for additional 5 seconds
6. Place drain pan under radiator and drain approximately 1.5 quarts of coolant by opening drain petcock
7. Photograph all vacuum line routing and electrical connections for reference

Procedure

1. 1

   Remove air intake system
   Loosen clamp at throttle body inlet and disconnect air intake tube. Disconnect MAF sensor electrical connector. Remove air filter housing by unclipping fasteners and lifting assembly out of engine bay. Remove intake resonator if equipped.
2. 2

   Disconnect throttle body connections
   Disconnect throttle position sensor electrical connector. Disconnect accelerator control cable if equipped (most are electronic throttle). Remove the four throttle body mounting bolts and carefully remove throttle body. Remove and discard old throttle body gasket.
   ℹ️Do not allow any debris to enter the intake manifold opening. Cover with clean shop towel.
   Torque spec

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

   Disconnect fuel system components
   Using fuel line disconnect tools, disconnect the fuel feed line from the fuel rail. Have shop rags ready to catch residual fuel. Disconnect fuel injector electrical connectors from all four injectors. Remove fuel rail mounting bolts and carefully lift fuel rail with injectors attached away from intake manifold.
   ⚠Keep fuel rail assembly clean and covered. Do not allow injector tips to contact any surface or debris.
   Torque spec

   Fuel Rail Bolts12 Nm (9 lb-ft)
4. 4

   Disconnect vacuum lines and hoses
   Disconnect brake booster vacuum hose from intake manifold. Disconnect PCV hose and valve from manifold. Disconnect EVAP purge valve hose. Disconnect all remaining vacuum lines from the intake manifold, referring to photos taken during preparation. Label each connection as removed.
5. 5

   Disconnect coolant hoses and electrical connections
   Disconnect coolant bypass hoses from the intake manifold (two hoses). Use pliers to release spring clamps and slide clamps away before removing hoses. Disconnect any remaining electrical connectors attached to sensors on the intake manifold including MAP sensor if equipped.
   ⚠Residual coolant will drain from hoses. Have drain pan positioned to catch coolant.
6. 6

   Remove intake manifold support bracket
   Locate the intake manifold support bracket on the passenger side of the manifold. Remove the mounting bolts securing the bracket to both the manifold and engine block. Remove bracket and set aside.
   Torque spec

   Mounting Bolts45 Nm (33 lb-ft)
7. 7

   Remove intake manifold
   Remove all intake manifold mounting bolts and nuts in reverse order from center outward pattern. Carefully lift intake manifold away from cylinder head. If manifold is stuck, gently tap with plastic mallet - do not pry between gasket surfaces. Remove and discard old intake manifold gasket.
   ⚠Do not pry on manifold mating surfaces as this will cause damage requiring machining or replacement.
   Torque spec

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

   Clean mating surfaces
   Use gasket scraper and wire brush to carefully clean all gasket material from intake manifold and cylinder head mating surfaces. Ensure surfaces are completely clean and smooth. Wipe surfaces with clean shop rag. Inspect for any cracks or damage. Cover cylinder head ports with clean rags to prevent debris entry.
   ⚠Do not gouge or scratch aluminum mating surfaces. Use plastic scraper if necessary.
9. 9

   Install new gasket and position manifold
   Remove rags covering cylinder head ports. Position new intake manifold gasket on cylinder head, ensuring all port openings align correctly and gasket locating pins engage properly. Carefully position intake manifold onto gasket, aligning all bolt holes.
10. 10

    Install and torque intake manifold bolts
    Hand-thread all intake manifold bolts and nuts to prevent cross-threading. Following the tightening sequence from center outward as specified in service manual, torque all fasteners to 25 Nm (18 lb-ft) using torque wrench. Complete tightening in two stages: first to 12 Nm, then final torque to 25 Nm.
    ⚠Proper tightening sequence is critical. Failure to follow sequence can warp manifold and cause vacuum leaks.
    Torque spec

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

    Reinstall support bracket
    Position intake manifold support bracket and install mounting bolts. Torque bracket mounting bolts to specification starting with manifold-side bolt first, then engine block bolt.
    Torque spec

    Mounting Bolts45 Nm (33 lb-ft)
12. 12

    Reconnect coolant hoses and vacuum lines
    Reconnect both coolant bypass hoses to intake manifold fittings and secure with spring clamps. Reconnect all vacuum lines to their original positions using photos for reference. Install PCV valve if removed, torquing to specification. Reconnect brake booster vacuum hose and EVAP purge hose.
    Torque spec

    PCV Valve8 Nm (6 lb-ft)
13. 13

    Reinstall fuel rail assembly
    Carefully position fuel rail with injectors onto intake manifold, ensuring all four injector O-rings seat properly into manifold ports. Install fuel rail mounting bolts and torque following service manual sequence. Reconnect all four fuel injector electrical connectors. Reconnect fuel feed line to fuel rail until it clicks into place.
    Torque spec

    Fuel Rail Bolts12 Nm (9 lb-ft)
14. 14

    Reinstall throttle body
    Install new throttle body gasket onto intake manifold. Position throttle body and install mounting bolts. Torque throttle body bolts following proper sequence per service manual. Reconnect throttle position sensor electrical connector.
    Torque spec

    Throttle Body Bolts10 Nm (7 lb-ft)
15. 15

    Reinstall air intake system and finalize
    Reinstall air filter housing and secure with clips. Reconnect MAF sensor electrical connector. Install intake tube to throttle body and tighten clamp securely. Reconnect negative battery terminal. Refill cooling system with Toyota Super Long Life Coolant to proper level. Reinstall engine cover.

Reassembly

1. Double-check all electrical connectors are fully seated and locked
2. Verify all vacuum lines are connected and routed correctly per reference photos
3. Ensure all coolant hose clamps are properly positioned and tight
4. Confirm fuel line connection is secure with audible click
5. Check that no tools or rags were left in engine bay

Verification

• Turn ignition to ON position without starting and listen for fuel pump priming (2 seconds). Check for fuel leaks around fuel rail and connections
• Start engine and allow to reach operating temperature while monitoring for coolant leaks at hose connections
• Check for vacuum leaks by listening for hissing sounds around intake manifold. Engine idle should be smooth and steady at approximately 650-750 RPM
• Verify no check engine light or diagnostic trouble codes are present
• Test drive vehicle to confirm normal throttle response and smooth acceleration with no hesitation
• Recheck coolant level after engine cools and top off if necessary

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