This procedure covers the removal and replacement of the downpipe (front exhaust pipe) on a 2018-2024 Toyota Camry with the 2.5L I4 engine, including oxygen sensor transfer and exhaust system reconnection.

Warnings

Tools required

Parts

• Downpipe/Front exhaust pipe assembly × 1 — Use OEM specification or quality aftermarket
• Exhaust flange gasket (manifold to downpipe) × 1 — Toyota 17451-0V010 or equivalent
• Exhaust flange gasket (downpipe to midpipe) × 1 — Use OEM specification
• Exhaust flange nuts/bolts × 1 — Replace if corroded

Preparation

1. Park vehicle on level surface and allow exhaust system to cool completely
2. Apply wheel chocks to rear wheels
3. Raise front of vehicle and support securely on jack stands at manufacturer lift points
4. Spray all exhaust fasteners with penetrating oil and allow to soak for at least 15 minutes (preferably 24 hours before starting)
5. Ensure adequate ventilation in work area

Procedure

1. 1

   Remove front oxygen sensor
   Disconnect the electrical connector for the front (upstream) oxygen sensor located near the exhaust manifold. Using a 22mm oxygen sensor socket, carefully unthread the sensor from the downpipe. Work slowly to avoid breaking the sensor or threads. Note the sensor orientation for reinstallation.
   ⚠Oxygen sensors are fragile. Do not use excessive force or allow the sensor to hang by its wire.
   Torque spec

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

   Remove rear oxygen sensor
   Locate the rear (downstream) oxygen sensor on the downpipe after the catalytic converter. Disconnect the electrical connector and use the 22mm oxygen sensor socket to remove the sensor. Keep sensors separate and labeled to ensure correct reinstallation positions.
   Torque spec

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

   Remove heat shields
   Remove the heat shield fasteners securing any heat shields to the downpipe or surrounding components using a 10mm socket. Some shields may be spot-welded and can be left in place if not interfering with removal. Set aside any removable shields for reinstallation.
   Torque spec

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

   Disconnect downpipe from exhaust manifold
   Locate the two-bolt flange connection at the exhaust manifold. Using a 14mm socket, remove the two nuts securing the downpipe to the manifold flange. Support the downpipe weight as you remove the last fastener. Remove and discard the old gasket from the flange connection.
   ⚠Manifold studs may break if excessive force is applied. If nuts are seized, apply heat carefully or use a nut splitter.
   Torque spec

   Manifold Nuts34 Nm (25 lb-ft)
5. 5

   Disconnect downpipe from midpipe
   Move to the rear flange connection where the downpipe connects to the midpipe. Using a 14mm socket, remove the two bolts or nuts from the spring-loaded flange connection. Note the presence and orientation of any spring bolts. Support the rear of the downpipe.
   Torque spec

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

   Remove exhaust hangers and downpipe
   Locate the rubber exhaust hangers supporting the downpipe (typically 1-2 hangers). Use an exhaust hanger removal tool or carefully pry the hangers from their mounts using a pry bar. Carefully lower and remove the downpipe assembly from the vehicle, maneuvering around the subframe and other components.
7. 7

   Prepare new downpipe and transfer sensors
   Clean the oxygen sensor threads on the new downpipe using a wire brush. Apply a thin coat of anti-seize compound to the threads of both oxygen sensors (threads only, not the sensor tip). Install the front oxygen sensor in the upstream position and rear sensor in the downstream position, hand-tightening first.
   ⚠Never apply anti-seize to the sensor tip or element. Only apply to the threaded portion.
   Torque spec

   O2 Sensor45 Nm (33 lb-ft)
8. 8

   Clean mating surfaces
   Use a wire brush and scraper to thoroughly clean the exhaust manifold flange and midpipe flange surfaces. Remove all traces of old gasket material and carbon buildup. Wipe clean with a rag. Inspect manifold studs and replace if damaged or corroded.
9. 9

   Install new downpipe
   Position the new exhaust flange gasket onto the exhaust manifold studs. Carefully maneuver the new downpipe into position, aligning it first with the manifold flange. Reinstall the exhaust hangers onto their mounts. Start the manifold nuts by hand to hold the downpipe in position.
10. 10

    Connect downpipe to midpipe
    Install the new flange gasket between the downpipe and midpipe connection. Align the flange and install the flange bolts or spring bolts. Apply anti-seize to bolt threads before installation. Start all fasteners by hand before tightening.
    ℹ️If equipped with spring bolts, ensure springs are properly positioned and compress evenly during tightening.
    Torque spec

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

    Torque all exhaust connections
    Using a torque wrench, tighten the manifold nuts to specification in a crisscross pattern. Then torque the rear flange bolts to specification. Tighten the oxygen sensors to specification. Ensure all connections are secure but do not overtighten.
    Torque spec

    Manifold Nuts34 Nm (25 lb-ft)

    Exhaust Flange Bolts45 Nm (33 lb-ft)

    O2 Sensor45 Nm (33 lb-ft)
12. 12

    Reinstall heat shields and connect sensors
    Reinstall any heat shields that were removed, torquing the fasteners to specification. Reconnect both oxygen sensor electrical connectors, ensuring they click securely into place and wiring is routed away from hot exhaust components and moving parts.
    Torque spec

    Heat Shield Bolts10 Nm (7 lb-ft)

Reassembly

1. Double-check all exhaust connections are torqued to specification
2. Verify all oxygen sensor connectors are fully seated and secured
3. Ensure exhaust hangers are properly seated and downpipe has adequate clearance from surrounding components
4. Verify no tools or parts have been left in the engine bay or under vehicle

Verification

• Lower vehicle from jack stands
• Start engine and listen for exhaust leaks at both flange connections. A slight hissing indicates a leak requiring retorquing or gasket replacement
• Allow engine to reach operating temperature while monitoring for leaks
• Check for exhaust odors in cabin which would indicate a leak
• Verify check engine light does not illuminate due to oxygen sensor issues
• Road test vehicle and verify normal performance with no unusual exhaust noise or vibration
• Recheck all fastener torque after initial heat cycle (recommended)

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