This procedure covers removal and replacement of the exhaust manifold on a 2019-2024 Toyota RAV4 with the 2.5L I4 gasoline engine, including heat shield, oxygen sensors, and related hardware.

Warnings

Tools required

Parts

• Exhaust manifold gasket × 1 — Use OEM specification
• Exhaust flange gasket × 1 — Use OEM specification
• Exhaust manifold studs (if damaged) × 8 — Use OEM specification
• Heat shield gasket or isolators (if equipped) × 1 — Use OEM specification

Preparation

1. Ensure engine is completely cold. Park vehicle on level surface and apply parking brake.
2. Disconnect negative battery terminal and isolate cable to prevent accidental starting.
3. Raise and safely support front of vehicle on jack stands.
4. Remove engine under covers to access exhaust system from below.
5. Apply penetrating oil to all exhaust manifold nuts, heat shield bolts, oxygen sensor, and exhaust flange bolts. Allow to soak while proceeding.
6. Take photos of oxygen sensor wiring routing and connector locations for reference during reinstallation.

Procedure

1. 1

   Remove oxygen sensor
   Disconnect oxygen sensor electrical connector. Using oxygen sensor socket, carefully remove the upstream oxygen sensor from the exhaust manifold. Work slowly to avoid breaking the sensor if corrosion is present. If sensor will be reused, inspect threads and clean carefully.
   Torque spec

   O2 Sensor47 Nm (35 lb-ft)
2. 2

   Remove heat shield
   Remove heat shield mounting bolts securing the exhaust manifold heat shield. Heat shield may be in multiple pieces. Work from top of engine compartment, removing upper shield sections first. Note bolt locations and any spacers or insulators for reinstallation.
   ⚠Heat shield bolts are small diameter and easily stripped. Use properly fitting socket and apply steady pressure.
   Torque spec

   Heat Shield Bolts10 Nm (7 lb-ft)
3. 3

   Disconnect exhaust flange
   Working from underneath the vehicle, locate the exhaust flange connection between the exhaust manifold and front exhaust pipe. Remove the exhaust flange bolts and separate the connection. Support the exhaust pipe with a wire or strap to prevent strain on downstream hangers.
   ⚠Flange bolts often seize. If bolt begins to strip, stop and apply heat or additional penetrating oil. Broken studs will require drilling and extraction.
   Torque spec

   Exhaust Flange Bolts45 Nm (33 lb-ft)
4. 4

   Remove exhaust hanger support
   If exhaust pipe is supported by nearby hangers that interfere with manifold removal, disconnect hanger bolts to allow additional clearance. Support exhaust system weight with jack or adjustable stand to prevent damage to downstream components.
   Torque spec

   Hanger Bolts20 Nm (15 lb-ft)
5. 5

   Access upper manifold area
   From engine compartment, remove any covers, air intake components, or wiring harnesses that obstruct access to exhaust manifold nuts. This may include engine cover, air intake tube, or ignition coil covers depending on specific model configuration. Label and photograph any disconnected components.
   Torque spec

   Cover Bolts16 Nm (12 lb-ft)
6. 6

   Remove exhaust manifold mounting nuts
   Working from the engine compartment, remove the exhaust manifold mounting nuts. There are typically 8 nuts securing the manifold to the cylinder head. Start with easily accessible nuts first. Use extensions and universal joints as needed to reach nuts near firewall. Work hot-to-cold (center outward) when loosening.
   ⚠If a stud begins to turn with the nut, stop immediately. Apply penetrating oil and allow to soak. Broken studs require cylinder head drilling/extraction which adds significant labor.
   Torque spec

   Exhaust Manifold Nuts30 Nm (22 lb-ft)
7. 7

   Remove exhaust manifold
   Once all nuts are removed, carefully work the exhaust manifold away from the cylinder head. Manifold may be tight against the head gasket. Gently work it free, being careful not to damage the cylinder head surface. Remove manifold from engine compartment. Angle may be tight; removal from below may be easier on some configurations.
8. 8

   Clean mating surfaces
   Remove old gasket material from cylinder head and exhaust manifold mating surfaces using a gasket scraper and wire brush. Inspect cylinder head surface for warping or damage. Check all studs for damage; replace any that are bent, stripped, or corroded. Clean stud threads with wire brush and blow out threaded holes with compressed air if available.
   ⚠Do not gouge or scratch cylinder head sealing surface. Damage to this surface can cause exhaust leaks that cannot be sealed with a new gasket.
9. 9

   Inspect and prepare new manifold
   If installing new manifold, compare with old unit to verify correct part. Inspect new or resurfaced manifold for cracks, especially around ports. Clean all surfaces. Transfer heat shield mounting points if applicable. Apply anti-seize compound to all exhaust manifold studs on cylinder head.
10. 10

    Install new gasket and manifold
    Position new exhaust manifold gasket on cylinder head studs. Carefully position exhaust manifold onto studs, ensuring gasket remains aligned. Start all exhaust manifold nuts by hand to ensure proper thread engagement before tightening any.
11. 11

    Torque exhaust manifold nuts
    Apply anti-seize compound to threads of exhaust manifold nuts. Torque nuts to specification in proper sequence (consult service manual for exact pattern; typically work from center outward, alternating sides). Perform torque sequence in multiple passes: first to 50% of final torque, then to full specification.
    ⚠Uneven or improper torque sequence can warp the manifold and cause exhaust leaks. Always follow manufacturer sequence.
    Torque spec

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

    Reinstall heat shield
    Position heat shield components over exhaust manifold. Install heat shield bolts and torque to specification following the proper sequence. Ensure shield is not making contact with any wiring or components that could be damaged by heat.
    Torque spec

    Heat Shield Bolts10 Nm (7 lb-ft)
13. 13

    Reconnect exhaust flange
    Position new exhaust flange gasket between manifold and front exhaust pipe. Align flange and install bolts. Apply anti-seize compound to flange bolt threads. Torque flange bolts to specification in a crossing pattern to ensure even gasket compression.
    Torque spec

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

    Reinstall oxygen sensor
    Apply anti-seize compound sparingly to oxygen sensor threads (avoid getting any on sensor tip). Install oxygen sensor and torque to specification using oxygen sensor socket. Reconnect electrical connector ensuring it clicks securely. Route wiring per original configuration to avoid heat damage.
    ⚠Do not over-torque oxygen sensor. Excessive torque can damage sensor housing or threads in manifold.
    Torque spec

    O2 Sensor47 Nm (35 lb-ft)
15. 15

    Reinstall remaining components
    Reconnect any exhaust hangers removed during disassembly, torquing hanger bolts to specification. Reinstall any covers, air intake components, or wiring harnesses removed for access. Reinstall engine under covers. Reconnect negative battery terminal.
    Torque spec

    Hanger Bolts20 Nm (15 lb-ft)

    Cover Bolts16 Nm (12 lb-ft)

Reassembly

1. Double-check that all exhaust manifold nuts are torqued to specification in proper sequence
2. Verify oxygen sensor electrical connector is fully seated and locked
3. Ensure heat shield is secure and not contacting any wiring or vulnerable components
4. Confirm exhaust system is properly supported and all hangers are connected

Verification

• Start engine and listen for exhaust leaks at manifold and flange connections. A stethoscope or length of hose can help locate small leaks.
• Allow engine to reach operating temperature and recheck for leaks while hot. Minor seepage may seal once system heat-cycles.
• Check for exhaust odor in cabin with engine running and HVAC on fresh air mode
• Verify no check engine light or oxygen sensor codes are present using OBD-II scanner
• After first 50-100 miles of driving, recheck exhaust manifold nut torque when engine is cold. Retorque if necessary as gasket may settle.
• Inspect heat shield for rattles or contact with other components during test drive

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