Exhaust Manifold

Remove and replace exhaust manifolds on a 1992 Dodge Viper 8.0L V10, including oxygen sensor removal, heat shield disassembly, and manifold gasket replacement.

Warnings

Tools required

Parts

• Exhaust manifold gasket set (left and right) × 1 — Use OEM specification
• Exhaust manifold nuts × 20 — Use OEM specification
• Exhaust flange gaskets × 2 — Use OEM specification

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 3 hours after engine operation)
4. Disconnect negative battery cable
5. Raise front of vehicle and support securely on jack stands
6. Spray all exhaust manifold nuts, flange bolts, and oxygen sensor threads with penetrating oil. Allow to soak for 30 minutes minimum

Procedure

1. 1

   Remove oxygen sensors
   Working from underneath the vehicle, locate the oxygen sensors in each exhaust manifold collector. Using an oxygen sensor socket, carefully unthread each sensor. The V10 typically has one upstream sensor per bank; confirm the exact number and location of oxygen sensors on this vehicle against factory documentation before proceeding. If sensors are seized, apply heat carefully to the manifold bung (not the sensor itself) and retry. Inspect sensor threads and manifold bungs for damage.
   ⚠Oxygen sensor threads are easily cross-threaded. Back out slowly and stop immediately if resistance is felt.
   Torque spec

   O2 Sensor47 Nm (35 lb-ft)
2. 2

   Remove exhaust flange bolts
   Locate the exhaust pipe-to-manifold flange connection on each side. Remove the flange bolts connecting the exhaust pipes to the manifold collectors. Support the exhaust pipes to prevent strain on hangers once disconnected. Confirm the exact number of flange bolts on each side against factory documentation before removal.
   Torque spec

   Exhaust Flange Bolt28 Nm (21 lb-ft)
3. 3

   Remove heat shields
   Remove the heat shield bolts securing the heat shields to each exhaust manifold. The shields are multi-piece and cover the manifolds and surrounding areas. Note the location and orientation of each shield section for reinstallation. The exact bolt count varies by shield section; inspect each shield carefully for all mounting points.
   Torque spec

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

   Access rear manifold fasteners
   From the top of the engine bay, identify all accessible exhaust manifold nuts. The rear cylinders (4, 5 on each bank) have very limited access. Use extensions and universal joints as needed. Verify the exact number and arrangement of exhaust manifold nuts per bank against factory documentation before removal.
5. 5

   Remove exhaust manifold fasteners - driver side
   Beginning at the front (cylinder 1), loosen the exhaust manifold nuts evenly, working from the outer ends toward the center (or per factory sequence). Work progressively toward the rear of the manifold. Remove all manifold nuts securing the left manifold, confirming the total count against factory documentation. If a stud breaks, note its location for extraction after manifold removal.
   ⚠Manifold studs often break on this engine. Work slowly and if a nut binds, stop and apply more penetrating oil.
   Torque spec

   Exhaust Manifold Nuts23 Nm (17 lb-ft)
6. 6

   Remove driver side exhaust manifold
   Carefully lift the left exhaust manifold away from the cylinder head. The manifold is heavy and may require rocking to break the gasket seal. Maneuver the manifold out of the engine bay, taking care not to damage adjacent components. Place the manifold on a workbench for inspection.
7. 7

   Remove exhaust manifold fasteners - passenger side
   Repeat the removal process for the right (passenger side) manifold. Remove all manifold nuts, loosening progressively from the outer nuts toward the center (or per factory sequence); confirm the total nut count against factory documentation. Access is equally challenging on this side.
   ⚠The passenger side rear cylinders have the most restricted access. Use a swivel socket if available.
   Torque spec

   Exhaust Manifold Nuts23 Nm (17 lb-ft)
8. 8

   Remove passenger side exhaust manifold
   Remove the right exhaust manifold from the cylinder head using the same technique as the left side. Inspect for warpage or cracks once removed.
9. 9

   Extract broken studs (if applicable)
   If any exhaust manifold studs broke during removal, extract them now using a stud extractor or left-hand drill bits. Clean the threads in the cylinder head with a thread chaser. This is critical for proper manifold seating.
10. 10

    Clean gasket surfaces
    Using a gasket scraper and wire brush, thoroughly clean all gasket material from the cylinder head exhaust ports and manifold mating surfaces. Inspect the cylinder head surface with a straight edge for warpage. The surface must be flat and clean. Clean the manifold collector flanges as well.
    ⚠Do not gouge or damage the aluminum cylinder head mating surface. Use plastic scrapers if necessary.
11. 11

    Inspect manifolds
    Inspect both manifolds for cracks, especially around the ports and collector area. Check the mating surface for warpage using a straight edge. Minor surface imperfections can be addressed with a flat file, but cracked manifolds must be replaced.
12. 12

    Install new gaskets and driver side manifold
    Position new exhaust manifold gaskets on the left cylinder head studs. Ensure gaskets are properly oriented (check for 'UP' markings). Carefully lift the left manifold into position and align all ports with the gasket. Start all 10 new manifold nuts by hand to ensure proper thread engagement.
13. 13

    Torque driver side manifold nuts
    Torque the left manifold nuts starting from the center fasteners and working outward toward the ends, in two or three progressive passes to the factory-specified torque. This ensures even clamping and prevents gasket failure. Apply a light coat of anti-seize to the nut threads if specified; note that anti-seize reduces friction, so verify whether the factory torque value assumes dry or lubricated threads and adjust accordingly.
    ℹ️The hot-to-cold torque sequence is critical for preventing gasket leaks and warpage.
    Torque spec

    Exhaust Manifold Nuts23 Nm (17 lb-ft)
14. 14

    Install new gaskets and passenger side manifold
    Position new exhaust manifold gaskets on the right cylinder head studs. Install the right manifold and start all 10 new nuts by hand.
15. 15

    Torque passenger side manifold nuts
    Torque the right manifold nuts starting from the center fasteners and working outward toward the ends, in progressive passes, matching the left side. Apply anti-seize to nut threads.
    Torque spec

    Exhaust Manifold Nuts23 Nm (17 lb-ft)
16. 16

    Reinstall heat shields
    Reinstall all heat shield sections in the reverse order of removal. Ensure shields are properly positioned and not contacting moving components or wiring. Torque heat shield bolts to specification.
    Torque spec

    Heat Shield Bolts10 Nm (7 lb-ft)
17. 17

    Reconnect exhaust pipes
    Install new flange gaskets between the manifold collectors and exhaust pipes. Align the pipes and install flange bolts. Apply anti-seize to bolt threads. Torque flange bolts to specification.
    Torque spec

    Exhaust Flange Bolt28 Nm (21 lb-ft)
18. 18

    Install oxygen sensors
    Apply anti-seize compound to the threads of both oxygen sensors (avoid getting compound on the sensor element). Thread sensors into manifold bungs by hand, then torque to specification using the oxygen sensor socket.
    ⚠Do not apply anti-seize to the sensor tip or element. Apply only to the threads.
    Torque spec

    O2 Sensor47 Nm (35 lb-ft)
19. 19

    Final inspection and battery reconnection
    Verify all fasteners are torqued, all heat shields are secure, and no tools or parts remain in the engine bay. Lower vehicle from jack stands. Reconnect the negative battery cable.

Reassembly

1. Torque all fasteners to specification in the sequences described
2. Use new gaskets and nuts for all exhaust manifold connections
3. Apply anti-seize to all exhaust fastener threads
4. Ensure heat shields are properly positioned before final torque

Verification

• Start engine and allow to idle. Listen for exhaust leaks at manifold-to-head and manifold-to-pipe connections
• Check for visible exhaust smoke or leaks around all manifold joints
• Allow engine to reach operating temperature and verify no leaks develop under heat
• Check for proper oxygen sensor function (no check engine light related to O2 sensors)
• Verify heat shields are not rattling or contacting other components

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