Exhaust Manifold Studs

This procedure covers the replacement of damaged or broken exhaust manifold studs on the 1.5L turbocharged engine, including removal of the turbocharger and exhaust components to access the studs.

Warnings

Tools required

Parts

• Exhaust manifold studs × 8 — Use OEM Honda specification, typically M8 or M10
• Turbocharger gasket × 1 — Use OEM Honda specification
• Exhaust manifold gasket × 1 — Use OEM Honda specification
• Downpipe flange gasket × 1 — Use OEM Honda specification
• Heat shield gasket/seal (if equipped) × 1 — Inspect and replace if damaged

Fluids

• Honda Type 2 Coolant (Blue) — 1 qt

Preparation

1. Ensure engine is completely cold (minimum 3 hours after last operation)
2. Disconnect negative battery terminal and wait 3 minutes
3. Raise and support vehicle on jack stands at all four corners for access
4. Remove engine cover by pulling upward on pull tabs
5. Drain coolant from radiator drain plug into suitable container for reuse
6. Remove air intake assembly and charge air cooler inlet piping to turbocharger
7. Apply penetrating oil to all exhaust fasteners and let soak for 30 minutes minimum

Procedure

1. 1

   Remove oxygen sensors
   Disconnect electrical connector from primary oxygen sensor (pre-turbo) and secondary oxygen sensor (post-turbo). Using oxygen sensor socket, carefully remove both sensors. If sensors are seized, apply heat and additional penetrating oil. Store sensors in clean area to prevent contamination of sensing elements.
   Torque spec

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

   Disconnect turbocharger oil and coolant lines
   Position drain pan under turbocharger. Disconnect oil feed line from top of turbocharger using appropriate wrench. Disconnect oil return line from bottom of turbocharger. Disconnect coolant inlet and outlet lines from turbocharger housing. Mark each line for proper reinstallation. Expect residual oil and coolant drainage.
   ⚠Oil and coolant lines are under slight residual pressure. Loosen slowly to prevent spraying.
3. 3

   Remove exhaust heat shields
   Remove all heat shield mounting bolts securing upper and lower heat shields around exhaust manifold and turbocharger. Carefully remove heat shields and set aside. Inspect shields for damage and replace if cracked or excessively corroded.
   Torque spec

   Heat Shield Bolts10 Nm (7 lb-ft)
4. 4

   Disconnect downpipe from turbocharger
   From underneath vehicle, remove three flange bolts connecting exhaust downpipe to turbocharger outlet. Support downpipe weight with jack stand or wire to prevent strain on rear exhaust hangers. Remove and discard downpipe gasket.
   Torque spec

   Exhaust Flange Bolts45 Nm (33 lb-ft)
5. 5

   Remove turbocharger assembly
   Remove bolts securing turbocharger to exhaust manifold. Carefully separate turbocharger from manifold studs. If turbocharger is stuck to studs, gently rock assembly while pulling away from engine. Remove and discard turbocharger gasket. Cover turbocharger inlet and outlet openings with clean shop towels to prevent debris entry.
   ⚠Turbocharger assembly weighs approximately 15-20 lbs. Support weight during removal to prevent dropping.
   Torque spec

   Exhaust Flange Bolts45 Nm (33 lb-ft)
6. 6

   Remove exhaust manifold
   Remove remaining nuts securing exhaust manifold to cylinder head studs. Note which studs are broken or damaged. Carefully remove exhaust manifold from cylinder head. If manifold is seized to studs, apply penetrating oil and use gentle rocking motion. Remove and discard exhaust manifold gasket. Inspect manifold for cracks or warping.
   ℹ️Count and document which studs are broken for parts ordering. Typically studs 1, 2, 7, and 8 are most prone to failure.
7. 7

   Extract broken studs
   For studs protruding from head: Use vice grips or stud extractor to turn counterclockwise. For flush or recessed broken studs: Center punch the exact center of broken stud. Drill pilot hole using bit smaller than stud diameter. Use left-hand drill bit or stud extractor, applying steady pressure while turning counterclockwise. If stud will not extract, apply heat to surrounding area (avoid direct heat on stud). Work slowly to avoid breaking extractor in hole.
   ⚠️If extractor breaks off in stud, extensive machine work will be required. Use high-quality extractors and work patiently.
   ⚠Keep drill perpendicular to cylinder head surface to avoid damaging threads or creating angled hole.
8. 8

   Clean and inspect cylinder head threads
   Once all broken studs are removed, use wire brush to clean stud holes. Run appropriate tap through each hole to clean and restore threads (typically M8x1.25 or M10x1.5 depending on stud location). Remove all debris using compressed air and shop vacuum. Inspect threads for damage. If threads are severely damaged, consult professional machinist for thread insert installation.
   ⚠Do not allow metal shavings to fall into engine. Cover all openings with clean rags during thread cleaning.
9. 9

   Install new exhaust manifold studs
   Apply thin coat of anti-seize to first 2-3 threads of new studs (not full length). Thread each new stud by hand into cylinder head until seated. Use double-nut method or stud installation tool to tighten studs to manufacturer specification (typically 15-20 Nm, but verify in service manual). Ensure all studs are perpendicular and fully seated. Wipe excess anti-seize from exposed stud threads.
   ℹ️Some technicians prefer to install studs finger-tight only and allow manifold installation to seat them. Follow Honda service manual recommendation.
10. 10

    Install exhaust manifold with new gasket
    Clean cylinder head mating surface with gasket scraper and brake cleaner. Position new exhaust manifold gasket onto studs with correct orientation (verify alignment tabs). Carefully slide exhaust manifold onto studs. Install washers and nuts finger-tight on all studs. Torque nuts in sequence from center outward in multiple passes: first to 15 Nm, then to final specification of 25-30 Nm (verify in service manual as this is not provided in torque database).
    ⚠Do not reuse old exhaust gaskets. Old gaskets will leak and cause exhaust odor in cabin.
11. 11

    Install turbocharger assembly
    Remove protective coverings from turbocharger openings. Apply thin coat of anti-seize to turbocharger stud threads. Position new turbocharger gasket onto manifold studs. Carefully align turbocharger onto studs and slide into place. Install washers and nuts, tightening in star pattern to specification.
    Torque spec

    Exhaust Flange Bolts45 Nm (33 lb-ft)
12. 12

    Reconnect turbocharger oil and coolant lines
    Reconnect coolant inlet and outlet lines to turbocharger using new crush washers if applicable. Torque to specification. Reconnect oil return line to bottom of turbocharger with new gasket. Reconnect oil feed line to top of turbocharger. Verify all connections are secure and properly aligned to prevent strain.
    ℹ️Before starting engine, oil feed line must be primed to prevent turbocharger damage during initial startup.
13. 13

    Reinstall downpipe and heat shields
    Position new downpipe gasket onto turbocharger outlet flange. Align downpipe to turbocharger and install three flange bolts with anti-seize compound. Torque to specification in star pattern. Reinstall exhaust heat shields and secure with bolts.
    Torque spec

    Exhaust Flange Bolts45 Nm (33 lb-ft)

    Heat Shield Bolts10 Nm (7 lb-ft)
14. 14

    Install oxygen sensors and reassemble
    Apply anti-seize compound to threads of both oxygen sensors (avoid getting compound on sensor tip). Install primary and secondary oxygen sensors and torque to specification. Reconnect electrical connectors ensuring positive lock engagement. Reinstall air intake assembly and charge air cooler piping. Refill cooling system with Honda Type 2 Blue coolant to proper level.
    Torque spec

    O2 Sensor45 Nm (33 lb-ft)

Reassembly

1. Verify all fasteners are torqued to specification before starting engine
2. Check that all coolant hoses are properly connected and clamps are tight
3. Ensure no tools or rags are left in engine bay
4. Reconnect negative battery terminal
5. Bleed cooling system by running engine with heater on full hot until thermostat opens and radiator fan cycles

Verification

• Start engine and verify turbocharger oil feed line is delivering oil (listen for unusual turbo noise which would indicate oil starvation)
• Allow engine to reach operating temperature and inspect all exhaust connections for leaks using visual inspection and listening for hissing sounds
• Check for coolant leaks at turbocharger coolant connections
• Verify no exhaust odor in cabin with HVAC system operating
• Test drive vehicle and verify normal boost pressure and no exhaust smell
• Re-check all exhaust flange bolt torque after 50-100 miles of driving as gaskets may settle

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