Exhaust Manifold Gasket

This procedure covers removal and replacement of the exhaust manifold gasket on the 2016-2024 Hyundai Tucson 2.5L I4 AWD engine, including manifold removal, gasket replacement, and proper torque sequence.

Warnings

Tools required

Parts

• Exhaust manifold gasket × 1 — Use OEM Hyundai/Kia gasket
• Exhaust manifold heat shield gasket (if equipped) × 1 — Use OEM specification
• Exhaust flange gasket × 1 — Use OEM specification
• Exhaust manifold studs (if damaged) × 8 — Use OEM specification
• EGR tube gasket (if equipped) × 1 — Use OEM specification

Fluids

• Hyundai/Kia Long Life Coolant (Green) — 0.5 qt

Preparation

1. Ensure engine is completely cold (12+ hours after last operation recommended)
2. Disconnect negative battery terminal and wait 3 minutes
3. Apply penetrating oil to all exhaust manifold nuts, heat shield bolts, O2 sensor, and flange bolts; allow to soak at least 30 minutes
4. Remove engine cover by pulling up firmly on front and rear edges
5. Remove air intake duct and air filter housing assembly for improved access
6. Drain approximately 1 quart of coolant from radiator drain to reduce spillage when disconnecting coolant hoses
7. Remove any wiring harness clips or brackets obstructing access to manifold
8. Place drain pan beneath vehicle to catch any residual fluids

Procedure

1. 1

   Remove heat shield
   Locate and remove all heat shield mounting bolts (typically 4-6 bolts) securing the exhaust manifold heat shield. The shield may be in multiple pieces. Carefully remove the heat shield and set aside. Inspect heat shield for cracks or damage and replace if necessary.
   Torque spec

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

   Disconnect oxygen sensor
   Locate the upstream oxygen sensor (before catalytic converter) on the exhaust manifold. Disconnect the electrical connector by pressing the release tab. Using an oxygen sensor socket, carefully loosen and remove the O2 sensor. Work slowly to prevent thread damage. If sensor is seized, apply additional penetrating oil and allow to soak, then retry.
   ⚠O2 sensors are fragile. Do not strike or drop the sensor. Keep sensor wire clean and free of contamination.
3. 3

   Disconnect EGR tube (if equipped)
   If your vehicle is equipped with an EGR system, locate the EGR tube connection to the exhaust manifold. Loosen and remove the EGR tube fitting nut. Carefully separate the tube from the manifold. Remove and discard the old EGR gasket.
4. 4

   Support exhaust system
   Position a jack stand or transmission jack under the catalytic converter/exhaust pipe to support the weight of the exhaust system. Place a block of wood on the jack to prevent damage to the exhaust. Raise just enough to take tension off the manifold flange connection.
   ⚠Failure to support the exhaust system will result in excessive stress on the manifold flange and may cause gasket installation issues or component damage.
5. 5

   Disconnect exhaust flange
   Locate the flange connection between the exhaust manifold and the front exhaust pipe (typically 2-3 bolts or nuts). Remove all flange fasteners. Separate the flange connection and remove the old gasket. Allow the exhaust pipe to rest on the support jack.
6. 6

   Remove exhaust manifold mounting nuts
   Working from the outer fasteners toward the center (hot-to-cold pattern), loosen all exhaust manifold mounting nuts approximately 1-2 turns each. Make multiple passes, gradually loosening each nut to prevent manifold warpage. Once all nuts are loose, remove them completely in the same pattern. Keep nuts in order if they have different lengths.
   ⚠If a stud breaks during removal, stop immediately and use a stud extractor. Do not attempt to remove the manifold with a broken stud as it may damage the cylinder head.
   Torque spec

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

   Remove exhaust manifold
   Carefully lift the exhaust manifold away from the cylinder head. The manifold may be stuck to the head due to carbon buildup. Gently rock the manifold if needed, but do not pry against the sealing surfaces. Once free, remove the manifold from the engine bay. Remove and discard the old manifold gasket.
   ⚠The manifold weighs approximately 15-20 lbs and may have sharp edges. Use proper lifting technique and wear gloves.
8. 8

   Clean sealing surfaces
   Using a plastic gasket scraper, carefully remove all old gasket material from the cylinder head mating surface. Take extreme care not to scratch or gouge the aluminum head surface. Use a wire brush to clean the exhaust manifold mating surface (cast iron can tolerate more aggressive cleaning). Spray both surfaces with brake cleaner and wipe clean with a lint-free cloth. Vacuum the area to remove all debris. Inspect cylinder head surface for cracks or damage.
   ⚠️Do not allow gasket debris to fall into the cylinder head ports. Cover the ports with clean shop towels during cleaning.
9. 9

   Inspect and prepare studs
   Inspect all exhaust manifold studs for damage, corrosion, or thread wear. If any studs are damaged, remove them using a stud removal tool and install new studs. Clean all stud threads with a wire brush. If installing new studs, apply anti-seize to the stud threads that thread into the cylinder head and torque to specification.
   Torque spec

   Exhaust Manifold Studs15 Nm (11 lb-ft)
10. 10

    Install new gasket and manifold
    Position the new exhaust manifold gasket onto the cylinder head studs, ensuring proper orientation (gasket will only fit one way). Carefully position the exhaust manifold onto the studs and gasket. Ensure manifold is fully seated against the gasket before installing any nuts. Thread all manifold nuts onto the studs by hand to prevent cross-threading.
    ℹ️Some OEM gaskets have an UP marking or coating on one side. Ensure the gasket is oriented correctly per manufacturer instructions.
11. 11

    Torque manifold nuts
    Apply a small amount of anti-seize compound to the threads of each manifold nut. Starting from the center fasteners and working outward (hot-to-cold pattern), torque the manifold nuts in three stages: first pass to 10 Nm (7 lb-ft), second pass to 20 Nm (15 lb-ft), and final pass to specification. Make at least two complete torque sequences at the final specification to ensure even clamping.
    ⚠Improper torque sequence or over-torquing can warp the manifold and cause exhaust leaks. Follow the hot-to-cold pattern strictly.
    Torque spec

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

    Reconnect exhaust flange
    Install a new exhaust flange gasket between the manifold and front exhaust pipe. Align the flange connection and thread in all fasteners by hand. Apply anti-seize to flange bolt threads. While supporting the exhaust system to maintain proper alignment, torque the flange bolts to specification in a crisscross pattern.
13. 13

    Install oxygen sensor
    Apply a small amount of anti-seize compound only to the threads of the oxygen sensor (avoid getting anti-seize on the sensor tip). Thread the O2 sensor into the manifold by hand, then torque to specification using the oxygen sensor socket. Reconnect the electrical connector and ensure the wire is routed away from hot surfaces.
    ⚠Do not apply anti-seize to the sensor element. Contamination will cause sensor failure and check engine lights.
14. 14

    Reinstall heat shield and accessories
    Position the heat shield over the exhaust manifold. Install and torque all heat shield bolts to specification. If equipped with EGR, install a new EGR tube gasket and reconnect the EGR tube, torquing the fitting nut to specification. Reinstall any wiring harness clips, brackets, or components removed during disassembly.
    Torque spec

    Heat Shield Bolts10 Nm (7 lb-ft)
15. 15

    Final assembly and fluid refill
    Reinstall the air filter housing assembly and air intake duct. Refill cooling system with Hyundai/Kia Long Life Coolant to proper level (approximately 0.5 quarts). Reinstall engine cover. Reconnect negative battery terminal. Remove support jack from exhaust system.
    ℹ️Bleed cooling system if air was introduced during hose disconnection by running engine to operating temperature with heater on full.

Reassembly

1. Verify all fasteners have been properly torqued according to specifications
2. Ensure all electrical connectors, hoses, and wiring are properly routed and secured
3. Double-check that no tools or shop towels were left in the engine bay
4. Verify exhaust system is properly supported and aligned with all hangers connected

Verification

• Start the engine and allow it to idle. Listen carefully for any exhaust leaks at the manifold gasket, flange connection, and O2 sensor
• With engine running, visually inspect all connections for signs of exhaust leakage (visible smoke or soot buildup)
• Allow engine to reach operating temperature and verify cooling system level is stable with no leaks
• Check for any check engine lights or diagnostic trouble codes related to O2 sensor or exhaust system
• Perform a test drive and verify normal engine performance with no exhaust smell in cabin
• After test drive, perform a final inspection of all connections while engine is warm, checking for leaks or loose fasteners
• Re-torque manifold nuts after first heat cycle (after engine cools) to verify proper clamping force is maintained

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