This procedure covers the replacement of exhaust manifold studs on the 2016-2024 Hyundai Tucson with the 2.5L I4 engine, including removal of the exhaust manifold and heat shields.

Warnings

Tools required

Parts

• Exhaust manifold studs (set) × 1 — Use OEM specification
• Exhaust manifold gasket × 1 — Use OEM specification
• Exhaust flange gasket × 1 — Use OEM specification
• Heat shield bolts (if damaged) × 1 — Use OEM specification
• O2 sensor (if damaged during removal) × 1 — Use OEM specification

Preparation

1. Ensure engine is completely cold to the touch (wait minimum 4 hours after last operation)
2. Disconnect negative battery terminal and isolate cable
3. Raise vehicle and support securely on jack stands at manufacturer lift points
4. Remove engine splash shield/undertray to access exhaust from below
5. Apply penetrating oil to all exhaust manifold studs, O2 sensor threads, and flange bolts. Allow to soak while gathering tools
6. Remove engine cover from top of engine bay if equipped

Procedure

1. 1

   Remove upper heat shield
   Remove the bolts securing the upper exhaust manifold heat shield. There are typically 3-4 bolts accessible from above. Keep track of any spacers or washers. If bolts are seized, apply additional penetrating oil and allow to soak.
   Torque spec

   Heat Shield Bolts10 Nm (7 lb-ft)
2. 2

   Disconnect oxygen sensor
   Locate the upstream oxygen sensor on the exhaust manifold. Disconnect the electrical connector by pressing the release tab. Using a 22mm O2 sensor socket, carefully remove the oxygen sensor. Work from below if necessary for better access. If sensor is seized, heat may be required but avoid damaging the wiring harness.
   ⚠O2 sensor threads are easily cross-threaded. Turn counterclockwise carefully and stop if resistance increases abnormally.
   Torque spec

   O2 Sensor45 Nm (33 lb-ft)
3. 3

   Remove exhaust front pipe connection
   Working from below, remove the bolts/nuts connecting the exhaust front pipe to the exhaust manifold flange. There are typically 2-3 spring-loaded bolts at this connection. Support the front pipe with a block or wire to prevent strain on downstream hangers. Remove and discard the old flange gasket.
   Torque spec

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

   Disconnect exhaust support bracket
   Remove any support brackets connecting the exhaust manifold or front pipe to the engine block or transmission. Note the orientation and mounting points for reassembly.
   Torque spec

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

   Remove lower heat shield (if equipped)
   From below the vehicle, remove any lower heat shield bolts securing a secondary heat shield between the manifold and engine block or subframe. Not all configurations have a lower shield.
   Torque spec

   Heat Shield Bolts10 Nm (7 lb-ft)
6. 6

   Remove exhaust manifold mounting nuts
   Working from above and below as needed, remove all nuts securing the exhaust manifold to the cylinder head studs. There are typically 6-8 nuts. Work in a cross-pattern starting from the outer nuts toward the center. Apply penetrating oil again if nuts are difficult to remove. If a stud begins to turn with the nut, stop and use a stud removal tool.
   ⚠If a stud starts rotating with the nut, stop immediately. The stud is likely seized in the head and continued force will break it. Use heat and penetrating oil before attempting extraction.
7. 7

   Remove exhaust manifold
   Carefully separate the exhaust manifold from the cylinder head. It may be stuck to the gasket. Use a pry bar in designated pry points if necessary, but avoid damaging the sealing surfaces. Maneuver the manifold out of the engine bay, which may require tilting or rotating to clear surrounding components. Remove and discard the old manifold gasket.
8. 8

   Remove damaged or all studs
   Using a stud removal tool or the double-nut method, remove the damaged studs from the cylinder head. If replacing all studs as preventive maintenance, remove all studs in sequence. Turn counterclockwise carefully. If a stud breaks, you will need to use a stud extractor or drill and tap the hole. Apply heat to the cylinder head around the stud if seized (avoid overheating aluminum head).
   ⚠Broken studs in aluminum heads require careful extraction to avoid damaging threads. If stud breaks below surface, professional machine shop repair may be necessary.
9. 9

   Clean cylinder head mounting surface
   Thoroughly clean all gasket material from the cylinder head exhaust port surface using a plastic scraper. Do not gouge the aluminum surface. Use a wire brush to clean the stud holes. Run the appropriate thread chaser or tap through each stud hole to clean threads and ensure proper thread engagement for new studs. Blow out holes with compressed air if available.
10. 10

    Install new exhaust manifold studs
    Apply a small amount of anti-seize to the threads of the new studs that will thread into the cylinder head (not the nut side). Thread each stud by hand into the cylinder head until finger-tight. Using the stud installation tool or double-nut method, tighten studs to manufacturer specification (typically 15-20 Nm for M8 studs on this engine, but verify with specific stud kit instructions). Install all studs to equal depth and ensure they are perpendicular to the head surface.
    ℹ️Stud torque specification may be included with replacement stud kit. If not specified, tighten firmly but do not exceed 20 Nm to avoid stripping aluminum threads.
11. 11

    Install exhaust manifold
    Position a new exhaust manifold gasket on the cylinder head studs. Ensure the gasket is oriented correctly (UP marking facing out if present). Carefully position the exhaust manifold onto the studs and gasket. Thread all manifold nuts onto the studs hand-tight before beginning torque sequence.
12. 12

    Torque exhaust manifold nuts
    Torque the exhaust manifold nuts in a cross-pattern sequence starting from the center and working outward. Perform the torque in two stages: first to 50% of final specification, then to the final specification listed in your stud kit instructions (typically 25-35 Nm for this application). Verify all nuts are properly seated and torqued.
13. 13

    Reinstall heat shields and brackets
    Reinstall the upper and lower heat shields (if equipped) using the original bolts or new bolts if damaged. Torque heat shield bolts to specification. Reinstall any support brackets removed earlier.
    Torque spec

    Heat Shield Bolts10 Nm (7 lb-ft)

    Hanger Bolts20 Nm (15 lb-ft)
14. 14

    Reconnect exhaust front pipe
    Position a new flange gasket between the exhaust manifold and front pipe. Align the front pipe to the manifold flange and install the flange bolts/nuts. Apply anti-seize to bolt threads as specified. Torque the flange bolts to specification in a cross-pattern.
    Torque spec

    Exhaust Flange Bolts45 Nm (33 lb-ft)
15. 15

    Reinstall oxygen sensor
    Apply a small amount of anti-seize to the O2 sensor threads only (avoid getting anti-seize on the sensor tip). Thread the oxygen sensor into the exhaust manifold by hand to avoid cross-threading. Torque to specification using the O2 sensor socket. Reconnect the electrical connector and ensure the wiring is routed away from hot exhaust components.
    Torque spec

    O2 Sensor45 Nm (33 lb-ft)

Reassembly

1. Reinstall engine cover if equipped
2. Reinstall engine splash shield/undertray using original fasteners
3. Lower vehicle from jack stands
4. Reconnect negative battery terminal

Verification

• Start engine and listen for exhaust leaks at manifold and flange connections. A slight ticking sound that disappears as the manifold heats and expands is normal for the first few seconds
• Allow engine to reach operating temperature and verify no exhaust leaks are present
• Check for any unusual noises or vibrations from the exhaust system
• Verify O2 sensor is functioning properly (no check engine light for O2 sensor codes)
• After first heat cycle, re-check manifold nut torque when engine is cold (optional but recommended for critical applications)

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