This procedure covers the replacement of the exhaust flex pipe on a 2016-2024 Hyundai Tucson with the 2.5L I4 engine and AWD, including proper exhaust component removal and installation with correct torque specifications.

Warnings

Tools required

Parts

• Flex pipe assembly × 1 — Use OEM specification or quality aftermarket equivalent
• Exhaust flange gasket (front) × 1 — Use OEM specification
• Exhaust flange gasket (rear) × 1 — Use OEM specification
• Flange bolts and nuts × 1 — Use OEM specification if corroded
• Exhaust hanger insulators × 1 — Replace if damaged

Preparation

1. Park vehicle on level surface and apply parking brake
2. Place wheel chocks behind rear wheels
3. Allow exhaust system to cool completely (minimum 2 hours after last engine operation)
4. Raise front of vehicle and support securely on jack stands at manufacturer-specified lift points
5. Spray all exhaust fasteners with penetrating oil and allow to soak for 15-30 minutes
6. Inspect undercarriage for any protective covers that may need removal for access

Procedure

1. 1

   Remove underbody covers if present
   Remove any plastic underbody covers or heat shields that obstruct access to the flex pipe area. These are typically secured with plastic clips and/or screws. Set aside for reinstallation.
   Torque spec

   Cover Screws11 Nm (8 lb-ft)
2. 2

   Disconnect oxygen sensor
   Locate the oxygen sensor(s) on or near the flex pipe assembly. Disconnect the electrical connector by pressing the release tab and pulling apart. If removing the sensor, use a 22mm O2 sensor socket and turn counterclockwise. Apply anti-seize to sensor threads before reinstallation.
   ⚠O2 sensor wiring is fragile. Support the sensor body while disconnecting to avoid pulling on wires.
   Torque spec

   O2 Sensor47 Nm (35 lb-ft)
3. 3

   Support exhaust system
   Place a jack or exhaust stand under the exhaust system near the flex pipe to support the weight of the exhaust once disconnected. This prevents damage to hangers and makes alignment easier during installation.
   ℹ️Do not fully support the weight yet, just provide gentle upward pressure to relieve stress on the flex pipe connections.
4. 4

   Remove front flange connection
   Remove the bolts or nuts connecting the front of the flex pipe to the catalytic converter or front exhaust pipe. There are typically 2-3 bolts in a circular flange pattern. Remove bolts evenly to prevent warping. Remove and discard the old gasket.
   ⚠If bolts are severely corroded and break, you may need to drill out the studs and install new ones.
   Torque spec

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

   Remove rear flange or clamp connection
   Remove the connection at the rear of the flex pipe. This may be a bolted flange connection or an exhaust clamp depending on configuration. If a clamp, loosen the clamp bolts and slide the clamp back. If a flange, remove bolts and old gasket.
   Torque spec

   Flange Bolts45 Nm (33 lb-ft)

   Exhaust Clamps55 Nm (41 lb-ft)
6. 6

   Disconnect exhaust hangers
   Disconnect any rubber exhaust hangers supporting the flex pipe or surrounding exhaust sections. Use a prying tool to pop the metal hook out of the rubber insulator. Inspect rubber insulators for cracking or deterioration and replace if necessary.
   Torque spec

   Hanger Bolts20 Nm (15 lb-ft)
7. 7

   Remove flex pipe assembly
   With all connections freed, carefully remove the flex pipe assembly from the vehicle. You may need to rotate or angle the pipe to clear frame members and other components. Lower the support jack as needed to provide clearance.
   ⚠Flex pipe may contain carbon deposits and debris. Wear gloves and eye protection to avoid irritation.
8. 8

   Clean mating surfaces
   Use a wire brush and gasket scraper to thoroughly clean all exhaust flange mating surfaces. Remove all old gasket material, carbon deposits, and corrosion. Clean surfaces ensure proper sealing and prevent exhaust leaks.
   ℹ️Do not gouge or damage the sealing surfaces. Clean until smooth and flat.
9. 9

   Install new gaskets
   Position new exhaust gaskets on the front and rear flange connections. Ensure gaskets are properly aligned with bolt holes and seated flat against the mating surface. Some gaskets have a directional orientation marked with 'UP' or arrows.
   ℹ️Do not use sealant on exhaust gaskets unless specifically required by the gasket manufacturer.
10. 10

    Position new flex pipe
    Raise the new flex pipe into position, aligning it with both front and rear connections. Use the support jack to hold the pipe at the correct height and angle. Reconnect exhaust hangers to their rubber insulators to help hold position.
    ℹ️Ensure the flex pipe is oriented correctly with any directional flow arrows pointing toward the rear of the vehicle.
11. 11

    Install front flange bolts
    Install the front flange bolts or nuts finger-tight, ensuring the gasket remains properly positioned. Do not fully tighten yet. Thread all fasteners before tightening any to ensure proper alignment.
    Torque spec

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

    Install rear connection
    Install the rear flange bolts finger-tight or position and loosely install the exhaust clamp. Again, ensure gasket is properly seated and all fasteners are started before tightening.
    Torque spec

    Flange Bolts45 Nm (33 lb-ft)

    Exhaust Clamps55 Nm (41 lb-ft)
13. 13

    Torque all exhaust fasteners
    Working from front to rear, torque all flange bolts to 45 Nm (33 lb-ft) in a crisscross pattern. If using exhaust clamps, torque clamp bolts to 55 Nm (41 lb-ft). Ensure connections are fully seated before final torquing.
    ⚠Do not overtighten exhaust fasteners as this can warp flanges and cause leaks or damage studs.
    Torque spec

    Flange Bolts45 Nm (33 lb-ft)

    Exhaust Clamps55 Nm (41 lb-ft)
14. 14

    Reinstall oxygen sensor
    If removed, apply a light coat of anti-seize compound to the oxygen sensor threads (avoid getting any on the sensor tip). Thread the sensor in by hand, then torque to 47 Nm (35 lb-ft) using an O2 sensor socket. Reconnect the electrical connector until it clicks.
    ⚠Do not apply anti-seize to the sensor tip or use excessive amounts on threads as this can affect sensor operation.
    Torque spec

    O2 Sensor47 Nm (35 lb-ft)
15. 15

    Reinstall underbody covers
    Reinstall any heat shields or underbody covers removed during disassembly. Torque cover screws to 11 Nm (8 lb-ft). Ensure all clips and fasteners are properly secured.
    Torque spec

    Cover Screws11 Nm (8 lb-ft)

Reassembly

1. Verify all exhaust connections are tight and properly torqued
2. Ensure all exhaust hangers are properly seated in their rubber insulators
3. Check that no wiring or hoses are in contact with the new flex pipe or exhaust system
4. Remove support jack from under exhaust system
5. Lower vehicle from jack stands

Verification

• Start the engine and listen for exhaust leaks at the flex pipe connections (hissing or ticking sounds indicate a leak)
• With engine running, carefully inspect all connections for visible exhaust gas escaping
• Check for proper exhaust system clearance - ensure no contact with frame, driveshaft, or suspension components
• Take vehicle for a test drive and verify no exhaust odors enter the cabin and no unusual exhaust noises are present
• After test drive, re-inspect all connections while engine is warm to ensure gaskets have seated properly and no leaks have developed
• If equipped with OBDII scanner, check for any oxygen sensor fault codes after repair

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