This procedure covers the replacement of exhaust manifold studs on the 2012-2017 Toyota Camry 2.5L I4 engine, including removal of exhaust components and heat shields to access the manifold mounting hardware.

Warnings

Tools required

Parts

• Exhaust manifold studs × 8 — Use OEM specification
• Exhaust manifold gasket × 1 — Use OEM specification
• Exhaust pipe gasket (donut gasket) × 1 — Use OEM specification
• Heat shield gasket/spacers (if damaged) × 1 — Use OEM specification

Preparation

1. Ensure engine is completely cold (not run for at least 4 hours)
2. Disconnect negative battery terminal
3. Raise vehicle and support securely on jack stands with wheel chocks in place
4. Remove front engine undercover/splash shield
5. Spray all exhaust fasteners with penetrating oil and allow to soak for 30+ minutes

Procedure

1. 1

   Remove oxygen sensors
   Disconnect the electrical connector from the upstream oxygen sensor. Using an O2 sensor socket, carefully remove the upstream oxygen sensor from the exhaust manifold. Remove the downstream sensor from the exhaust pipe if it interferes with pipe removal. Keep sensors protected from damage.
   Torque spec

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

   Remove exhaust heat shields
   Remove the upper and lower exhaust manifold heat shields by removing the mounting bolts. These shields are typically held by 10mm bolts. Note the location of any spacers or insulators for reassembly.
   Torque spec

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

   Disconnect exhaust pipe from manifold
   From underneath the vehicle, support the front exhaust pipe. Remove the three bolts connecting the exhaust pipe flange to the exhaust manifold. The pipe may need to be pushed down slightly to separate from the manifold. Remove and discard the old donut gasket.
   ⚠Exhaust flange bolts are prone to seizing. Apply penetrating oil and use proper technique to avoid breaking bolts in the manifold.
   Torque spec

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

   Support exhaust pipe
   Remove the exhaust hanger bolt(s) near the front pipe to allow the exhaust system to hang freely without stressing components. Support the exhaust pipe with a suitable stand or wire to prevent damage to downstream components.
   Torque spec

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

   Remove exhaust manifold
   Remove all exhaust manifold mounting nuts from the cylinder head studs (typically 8 nuts total). Carefully remove the exhaust manifold from the cylinder head. The manifold does not need to be completely removed if studs are accessible, but removal provides better access and allows manifold inspection.
   ℹ️If studs are broken or missing nuts, note their positions. Some studs may come out with the manifold still attached.
6. 6

   Remove old studs from cylinder head
   Using a stud remover tool or double-nut method, carefully remove all exhaust manifold studs from the cylinder head. Turn counter-clockwise slowly and steadily. If a stud breaks, stop immediately and use appropriate extraction methods. Clean the stud holes thoroughly with a wire brush and compressed air.
   ⚠️Apply steady pressure only. Sudden force can break studs below the surface, requiring drilling and extraction that risks cylinder head damage.
   ⚠If a stud breaks flush or below surface, professional extraction may be necessary to avoid cylinder head damage.
7. 7

   Clean and inspect cylinder head threads
   Thoroughly clean all stud mounting holes in the cylinder head. Use a thread chaser or M10 x 1.25 tap to clean the threads if necessary. Remove all carbon deposits, old thread locker, and debris. Inspect threads for damage. Verify all holes are clean by test-threading a new stud by hand.
   ⚠Do not force tap into threads. If significant resistance is encountered, threads may be damaged and require professional repair.
8. 8

   Install new exhaust manifold studs
   Apply a small amount of anti-seize compound to the stud threads that will thread into the cylinder head (not the nut side). Thread each new stud into the cylinder head by hand first to ensure proper alignment. Use a stud installer tool or double-nut method to tighten studs firmly into the cylinder head, but do not over-torque.
   ℹ️Studs should be snug but not torqued to maximum. The cylinder head is aluminum and over-tightening studs can strip threads.
9. 9

   Install exhaust manifold with new gasket
   Place a new exhaust manifold gasket onto the cylinder head, aligning all ports and stud holes. Carefully install the exhaust manifold onto the studs, ensuring the gasket remains properly positioned. Install all manifold nuts finger-tight initially.
   ℹ️Ensure the gasket is oriented correctly with any UP markings visible and all port openings aligned.
10. 10

    Torque exhaust manifold nuts
    Using a torque wrench, tighten the exhaust manifold nuts in a spiral pattern from the center outward. Torque to specification in two steps: first to 50% of final torque, then to full specification. This ensures even gasket compression and prevents warping.
    ℹ️While the torque spec database lists 'Flange Bolts' at 47 Nm, verify this applies to manifold-to-head nuts for your specific application. Use the 47 Nm specification for manifold mounting nuts.
    Torque spec

    Exhaust Flange Bolts45 Nm (33 lb-ft)
11. 11

    Reinstall heat shields
    Reinstall the lower and upper exhaust manifold heat shields with any spacers or insulators in their original positions. Tighten heat shield bolts to specification.
    Torque spec

    Heat Shield Bolts10 Nm (7 lb-ft)
12. 12

    Reconnect exhaust pipe
    Install a new donut gasket between the exhaust manifold and front exhaust pipe. Align the exhaust pipe flange with the manifold flange. Apply anti-seize to the exhaust flange bolt threads and install the three flange bolts. Torque bolts to specification in a cross pattern.
    Torque spec

    Exhaust Flange Bolts45 Nm (33 lb-ft)
13. 13

    Reinstall exhaust hangers and oxygen sensors
    Reconnect the exhaust hanger bolts to secure the exhaust system properly. Apply anti-seize compound to oxygen sensor threads only (avoid getting anti-seize on the sensor tip). Install upstream and downstream oxygen sensors and torque to specification. Reconnect all oxygen sensor electrical connectors.
    ⚠Do not apply anti-seize to oxygen sensor tips or contamination will cause sensor failure and check engine lights.
    Torque spec

    Hanger Bolts20 Nm (15 lb-ft)

    O2 Sensor45 Nm (33 lb-ft)

Reassembly

1. Reinstall front engine undercover/splash shield
2. Lower vehicle from jack stands
3. Reconnect negative battery terminal
4. Clear any diagnostic trouble codes if check engine light was on due to O2 sensor disconnection

Verification

• Start the engine and listen for any exhaust leaks at the manifold and pipe connection points
• Inspect all connections while engine is running for visible exhaust gas escape
• Allow engine to reach operating temperature and verify no leaks develop
• Check for proper oxygen sensor operation and ensure no check engine light appears
• After first heat cycle, optionally re-check manifold nut torque when engine is cold

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