This procedure covers the removal and replacement of broken or damaged exhaust manifold studs on the 2018-2024 Toyota Camry 2.5L I4 engine, including manifold removal and stud extraction.

Warnings

Tools required

Parts

• Exhaust manifold studs × 8 — Use OEM specification
• Exhaust manifold gasket × 1 — Use OEM specification
• Exhaust manifold to catalytic converter gasket/donut × 1 — Use OEM specification
• High temperature anti-seize compound × 1 — Copper or nickel-based
• Oxygen sensor (if damaged) × 1 — Replace only if necessary

Preparation

1. Ensure engine is completely cold (minimum 3 hours after last operation)
2. Disconnect negative battery terminal
3. Raise and support vehicle on jack stands if additional clearance is needed
4. Remove engine cover if equipped
5. Spray all exhaust fasteners, studs, and oxygen sensor threads with penetrating oil and allow to soak (repeat several times over 30 minutes)

Procedure

1. 1

   Remove heat shield and oxygen sensor
   Remove the heat shield bolts securing the upper heat shield to the exhaust manifold. Using a 22mm oxygen sensor socket, carefully remove the upstream oxygen sensor from the exhaust manifold. If sensor is seized, apply heat and additional penetrating oil. Apply anti-seize to sensor threads before storage to prevent galling during reinstallation.
   ⚠Oxygen sensor threads are fragile. Use proper socket and do not over-torque or cross-thread during removal or installation.
   Torque spec

   Heat Shield Bolts10 Nm (7 lb-ft)

   O2 Sensor45 Nm (33 lb-ft)
2. 2

   Disconnect exhaust pipe from manifold
   Support the front exhaust pipe with a jack stand or wire to prevent stress on downstream components. Remove the exhaust flange bolts connecting the catalytic converter to the exhaust manifold. There are typically 2 bolts and 1 spring-loaded compression joint. Carefully separate the connection and lower the exhaust pipe slightly.
   Torque spec

   Exhaust Flange Bolts45 Nm (33 lb-ft)
3. 3

   Remove intake air components
   Disconnect the air intake duct from the throttle body. Remove any brackets or clips securing the air box that interfere with manifold access. Move components aside to create workspace at the front of the engine. Label any vacuum lines or sensors disconnected for proper reassembly.
4. 4

   Remove exhaust manifold nuts
   Working from the outside nuts toward the center, carefully remove all manifold nuts from the studs. There are 8 studs total securing the manifold to the cylinder head. If a nut is seized on a stud, apply heat with a propane torch and additional penetrating oil. If the stud begins to turn with the nut, stop immediately and mark that stud location for replacement.
   ⚠Do not force seized nuts. If a stud begins rotating, it is already damaged and will need extraction. Forcing it may break the stud below the surface.
   Torque spec

   Manifold Nuts34 Nm (25 lb-ft)
5. 5

   Remove exhaust manifold assembly
   Carefully pull the exhaust manifold away from the cylinder head. The manifold may be stuck to the gasket. Gently tap with a rubber mallet if needed. Once free, remove the manifold from the engine bay. Remove and discard the old gasket. Inspect the manifold mating surface for warping or cracks.
6. 6

   Assess damaged studs and prepare for extraction
   Identify all broken, damaged, or seized studs that require removal. Clean the area around each stud with a wire brush. Use a center punch to mark the exact center of each broken stud. Apply penetrating oil directly into the center punch mark and allow to soak for 15 minutes. If stud is protruding, attempt removal with locking pliers or a stud removal tool first.
7. 7

   Extract broken studs
   For studs broken flush or below the surface: Using a left-hand drill bit slightly smaller than the stud minor diameter (approximately 7mm for M10 studs), carefully drill into the center of the stud. Keep the drill perfectly perpendicular to the head surface. Drill to a depth of approximately 15-20mm. The left-hand rotation may extract the stud during drilling. If not, insert an appropriately sized stud extractor into the hole and slowly turn counterclockwise with a tap handle. Apply heat to the surrounding area if the stud does not move.
   ⚠️Keep drill bit perfectly straight. Angling the drill will damage cylinder head threads and may require helicoil repair or professional machining.
   ⚠Use steady pressure but do not force the extractor. If excessive force is needed, drill slightly deeper or apply more heat. Breaking an extractor in the hole creates a severe repair problem.
8. 8

   Clean and inspect threads
   Once all damaged studs are removed, thoroughly clean each threaded hole in the cylinder head. Use a wire brush and compressed air to remove all debris, old thread locker, and carbon buildup. Run an M10 x 1.25 thread chaser or tap through each hole to clean and verify thread condition. Inspect threads carefully for damage. If threads are damaged, helicoil repair will be required before proceeding.
   ℹ️If more than 2 thread holes are damaged and require helicoil repair, consider having a machine shop perform the work to ensure proper alignment and depth.
9. 9

   Install new studs
   Apply a small amount of high-temperature anti-seize compound to the threads of each new stud (coarse thread end that goes into the head). Thread each stud into the cylinder head by hand until fully seated. Use two nuts locked together on the stud end or a stud installation tool to tighten the studs snugly into the head. Do not over-tighten. The stud should be firmly seated but not under excessive tension.
   ⚠Do not use thread locker on exhaust manifold studs. Use only high-temperature anti-seize compound rated for exhaust applications.
10. 10

    Clean manifold and head mating surfaces
    Using a gasket scraper and wire brush, thoroughly clean both the cylinder head mating surface and the exhaust manifold mating surface. Remove all old gasket material, carbon deposits, and debris. Wipe surfaces clean with a lint-free cloth. Inspect both surfaces for warping, cracks, or damage.
11. 11

    Install new gasket and manifold
    Position the new exhaust manifold gasket onto the studs and against the cylinder head surface. Carefully position the exhaust manifold over the studs and onto the gasket. Ensure all studs pass through their corresponding holes in the manifold. Thread all manifold nuts onto the studs by hand before tightening any of them.
12. 12

    Torque manifold nuts to specification
    Apply a thin coat of high-temperature anti-seize to the threads of each manifold nut. Tighten the manifold nuts in a spiral pattern starting from the center and working outward. Perform initial tightening to finger-tight plus one turn, then torque all nuts to specification in the same spiral pattern. Make a second pass to verify all nuts are properly torqued.
    ℹ️Proper torque sequence prevents manifold warping and ensures even gasket compression. Always work from center outward.
    Torque spec

    Manifold Nuts34 Nm (25 lb-ft)
13. 13

    Reconnect exhaust pipe and install oxygen sensor
    Position a new exhaust donut gasket between the manifold and catalytic converter flange. Raise the exhaust pipe into position and install the flange bolts with anti-seize applied to threads. Torque flange bolts to specification. Install the oxygen sensor with anti-seize applied only to the threads (keep sensor tip clean), and torque to specification.
    Torque spec

    Exhaust Flange Bolts45 Nm (33 lb-ft)

    O2 Sensor45 Nm (33 lb-ft)
14. 14

    Reinstall heat shield and air intake components
    Reinstall the exhaust manifold heat shield and torque heat shield bolts to specification. Reconnect all air intake components, vacuum lines, and sensors that were removed. Ensure all connections are secure and properly seated. Reinstall engine cover if equipped.
    Torque spec

    Heat Shield Bolts10 Nm (7 lb-ft)

Reassembly

1. Reconnect negative battery terminal
2. Double-check that all fasteners are tightened and all connections are secure
3. Verify no tools or materials were left in the engine bay

Verification

• Start the engine and listen for exhaust leaks at the manifold-to-head interface and manifold-to-pipe connection
• Allow engine to reach operating temperature and inspect all connections for leaks or unusual sounds
• Check for proper oxygen sensor operation (no check engine light related to oxygen sensor codes)
• Perform a test drive and verify normal engine performance with no unusual noises or vibrations
• After the first heat cycle, inspect all manifold nuts and exhaust flange bolts for proper tightness (optional re-torque after 50-100 miles)

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