Front Pipe

Remove and replace the front exhaust pipe (headpipe) assembly connecting the exhaust manifolds to the catalytic converters on the 1992 Dodge Viper 8.0L V10.

Warnings

Tools required

Parts

• Front exhaust pipe gasket set × 1 — Use OEM specification
• Exhaust manifold flange gaskets × 2 — Use OEM specification
• Oxygen sensor (if damaged) × 1 — Use OEM specification

Preparation

1. Park vehicle on level, solid surface and apply parking brake.
2. Place wheel chocks behind rear wheels.
3. Allow exhaust system to cool completely if vehicle has been running recently (minimum 2 hours).
4. Raise front of vehicle using floor jack at designated front jacking point.
5. Support vehicle securely on jack stands positioned under frame rails.
6. Spray all exhaust flange bolts, manifold nuts, oxygen sensor threads, and hanger bolts with penetrating oil. Allow to soak for 15-30 minutes before beginning disassembly.

Procedure

1. 1

   Disconnect oxygen sensor
   If equipped, locate the oxygen sensor mounted in the front pipe assembly. Note: the 1992 Viper was not originally equipped with a catalytic converter or oxygen sensor from the factory, so this step may not apply unless the exhaust has been modified. Disconnect the electrical connector by pressing the release tab and pulling straight apart. If removing sensor for reuse, use a 22mm oxygen sensor socket or 7/8" wrench to carefully unthread the sensor counterclockwise. Set aside in a clean location if reusing.
2. 2

   Remove front pipe to catalytic converter connection
   Locate the flanged connection where the front pipe meets the downstream exhaust (mid-pipe/muffler section). Note: 1992 Vipers were not factory-equipped with catalytic converters. Remove the 2 flange bolts at this connection using a 15mm socket and ratchet. Support the front pipe weight with one hand as you remove the final bolt to prevent the pipe from dropping.
   Torque spec

   Exhaust Flange Bolts31 Nm (23 lb-ft)
3. 3

   Disconnect exhaust hangers
   Locate the rubber exhaust hangers supporting the front pipe assembly. There are typically 2 hanger points along the front pipe. Use a pry bar or large flathead screwdriver to carefully work the hanger loops off the mounting brackets. Work the rubber isolator off the hanger stud by pulling downward on the pipe while prying.
4. 4

   Remove heat shields
   The front pipe has heat shields protecting nearby components. Remove the heat shield mounting bolts using a 15mm socket. Remove the heat shield mounting bolts; verify the exact count and locations against the factory service manual for this vehicle. Set shields and hardware aside.
   Torque spec

   Heat Shield Bolts10 Nm (7 lb-ft)
5. 5

   Disconnect front pipe from exhaust manifolds
   Working from underneath the vehicle, locate the two flange connections where the front pipe mates to the left and right exhaust manifolds. Each flange is secured to the manifold with the factory-specified number of nuts. Verify the exact count and socket size against the FSM before loosening these nuts with a breaker bar. Remove all manifold nuts and carefully separate the front pipe from both manifolds. The pipe assembly may be heavy; support it carefully and lower it down out of the vehicle.
   ⚠Front pipe assembly weighs approximately 25-30 lbs. Use caution when lowering to avoid personal injury or damage to vehicle components.
   Torque spec

   Manifold Nuts34 Nm (25 lb-ft)
6. 6

   Inspect and clean mating surfaces
   With the front pipe removed, inspect all flange surfaces for damage, warping, or excessive corrosion. Use a wire brush to thoroughly clean all gasket surfaces on the exhaust manifolds, front pipe flanges, and catalytic converter connection. Remove all old gasket material. Inspect manifold studs for damage or thread wear. Check the oxygen sensor bung in the new or existing pipe for thread damage.
7. 7

   Install oxygen sensor in new front pipe
   If installing a new or replacement oxygen sensor, apply a thin coat of anti-seize compound to the sensor threads only (avoid getting anti-seize on the sensor tip). Thread the sensor into the front pipe oxygen sensor bung by hand to ensure proper thread engagement. Tighten the sensor to specification using an oxygen sensor socket and torque wrench.
   Torque spec

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

   Position new front pipe and install manifold gaskets
   Install new exhaust manifold flange gaskets onto the manifold studs. Position the new front pipe assembly up into place, aligning the front pipe flanges with both exhaust manifolds. The pipe must align simultaneously with both left and right manifolds. You may need an assistant or use a jack with wood block to support the pipe weight during alignment.
9. 9

   Install manifold flange nuts
   Apply a small amount of anti-seize compound to the threads of the manifold studs. Thread all 6 manifold nuts onto the studs by hand to ensure proper thread engagement. Tighten the nuts in a criss-cross pattern to specification using an 18mm socket and torque wrench. Torque in two stages: first to approximately 50% of the FSM final torque value, then to the final specification per the factory service manual.
   Torque spec

   Manifold Nuts34 Nm (25 lb-ft)
10. 10

    Reinstall heat shields
    Position the heat shields back into their original locations around the front pipe. Install all heat shield mounting bolts and tighten to specification using a 15mm socket and torque wrench.
    Torque spec

    Heat Shield Bolts10 Nm (7 lb-ft)
11. 11

    Reconnect exhaust hangers
    Lift the rear section of the front pipe and align the hanger loops with the rubber isolator mounting studs. Work each rubber isolator back onto its mounting stud, ensuring full engagement. You may need to use a pry bar or pull the pipe into position to align the hangers properly.
12. 12

    Connect front pipe to catalytic converter
    Install a new gasket at the front pipe to catalytic converter flange connection. Align the flanges and install the 2 flange bolts. Apply anti-seize to the bolt threads. Tighten the bolts to specification using a 15mm socket and torque wrench.
    Torque spec

    Exhaust Flange Bolts31 Nm (23 lb-ft)
13. 13

    Reconnect oxygen sensor electrical connector
    Route the oxygen sensor wiring harness to avoid contact with hot exhaust components. Connect the oxygen sensor electrical connector by pushing together until the locking tab clicks into place. Verify the connection is secure by gently tugging on the connector.

Reassembly

1. Verify all exhaust connections are tight and all fasteners have been installed.
2. Ensure oxygen sensor wiring is properly routed away from heat sources and moving components.
3. Double-check that all rubber exhaust hangers are properly seated on their mounting studs.
4. Remove jack stands and carefully lower vehicle to the ground.

Verification

• Start the engine and listen for exhaust leaks at all connection points (manifold flanges, catalytic converter flange, and oxygen sensor). A hissing sound indicates a leak requiring immediate correction.
• With engine at idle, visually inspect all connections for exhaust gas escaping. Look for smoke or soot marks indicating leaks.
• Allow engine to reach operating temperature and recheck all connections for leaks.
• Verify oxygen sensor is functioning properly by checking for diagnostic trouble codes using a scan tool. No oxygen sensor codes should be present.
• After first 50-100 miles of operation, recheck all exhaust flange nuts and bolts for proper torque, as they may settle during initial heat cycling.

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