Exhaust Manifold Gasket

This procedure replaces the exhaust manifold gasket on the 5.9L Cummins diesel engine, addressing exhaust leaks and restoring proper sealing between the manifold and cylinder head.

Warnings

Tools required

Parts

• Exhaust manifold gasket (6 cylinder) × 1 — Use OEM specification
• Exhaust manifold studs (if damaged) × 12 — Use OEM specification
• Heat shield gasket/seal (if equipped) × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Allow engine to cool completely (minimum 3 hours after running)
3. Disconnect both battery negative terminals to prevent accidental starter engagement
4. Apply penetrating oil to all exhaust manifold nuts and studs, allow to soak
5. Raise and support vehicle on jack stands if additional underside access is needed
6. Remove engine cover if equipped

Procedure

1. 1

   Disconnect exhaust downpipe
   Locate the exhaust downpipe connection at the turbocharger or exhaust manifold outlet. Spray fasteners with penetrating oil. Remove the bolts or v-band clamp securing the downpipe to the exhaust outlet. Support the downpipe and lower it away from the manifold, taking care not to damage oxygen sensors if present. You may need to remove exhaust hangers for additional clearance.
2. 2

   Remove heat shield (if equipped)
   If your manifold has a heat shield installed, remove the mounting bolts securing it to the exhaust manifold. On the 5.9L Cummins, this is typically located on the passenger side. Remove the heat shield and set aside. Inspect the shield for damage or warping.
   Torque spec

   Heat Shield Bolts10 Nm (7 lb-ft)
3. 3

   Remove EGR components (if equipped)
   The 5.9L Cummins in the 2007 Ram 3500 typically does not use EGR. If no EGR components are present at the exhaust manifold, skip this step. Remove mounting bolts and carefully move the EGR tube assembly out of the way. You may need to disconnect the EGR valve connection at the intake manifold for clearance.
4. 4

   Remove turbocharger oil drain tube
   Disconnect the turbocharger oil drain tube from the turbo housing and the oil pan return. This provides necessary clearance for manifold removal on the passenger side. Cap or plug openings to prevent debris entry.
5. 5

   Loosen exhaust manifold nuts in sequence
   Working from the center outward, gradually loosen all exhaust manifold nuts in an even pattern. Loosen each nut 1-2 turns at a time in multiple passes to prevent warping the manifold. Use a 12mm deep socket and hand ratchet only—no impact tools. If a stud begins to turn with the nut, stop immediately and apply more penetrating oil.
   ⚠Studs are extremely prone to breaking. Work slowly and carefully. If resistance is excessive, apply heat with a propane torch and allow to cool before attempting again.
6. 6

   Remove exhaust manifold
   Once all nuts are removed, carefully work the exhaust manifold away from the cylinder head. The manifold may be stuck to the gasket. Use a pry bar gently between the manifold flange and head (not on machined surfaces) to break the seal. Lift the manifold away from the engine. Inspect the manifold for cracks, especially around the ports.
7. 7

   Remove old gasket and inspect studs
   Remove the old exhaust manifold gasket from the cylinder head. Use a plastic scraper and brass wire brush to clean all gasket material from the head mating surface. Inspect all 12 exhaust studs for damage, corrosion, or thread wear. If any studs are damaged or turn when attempting to install nuts, they must be replaced. Clean stud threads with a wire brush.
8. 8

   Replace damaged studs (if necessary)
   If any studs require replacement, remove them using a stud removal tool or double-nut method. Clean the threaded holes in the cylinder head with a thread chaser. Apply a small amount of anti-seize to the stud threads that screw into the head. Install new studs and torque to the factory specification (verify value in the FSM). Proceed once studs are seated.
   Torque spec

   Exhaust Manifold Studs15 Nm (11 lb-ft)
9. 9

   Clean manifold mating surface
   Thoroughly clean the exhaust manifold mating surface using a brass wire brush and plastic scraper. Remove all old gasket material, carbon deposits, and corrosion. The surface must be completely clean and flat for proper sealing. Wipe down with a clean shop towel and brake cleaner.
10. 10

    Install new gasket and position manifold
    Position the new exhaust manifold gasket on the cylinder head studs. The gasket should fit over all 12 studs and seat flush against the head. Carefully lift the exhaust manifold into position, aligning all ports with the gasket. Thread on all 12 nuts hand-tight to hold the manifold in place. Verify the gasket has not shifted out of position.
11. 11

    Torque manifold nuts in sequence
    Apply a thin coat of anti-seize compound to the threads of all exhaust manifold nuts. Working from the center fasteners outward in an even pattern, torque all nuts in progressive passes. Final torque is approximately 32 Nm (24 lb-ft). Verify the exact final torque and tightening sequence against the factory service manual for the 5.9L Cummins.
    ℹ️The hot-to-cold sequence (cylinder 6 to 1) is critical for proper gasket compression and preventing leaks. Always start at the front of the engine.
    Torque spec

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

    Reinstall heat shield
    If equipped with a heat shield, position it over the manifold with new gasket/seal if necessary. Install mounting bolts and torque to specification. Ensure the heat shield does not contact any wiring or hoses.
    Torque spec

    Heat Shield Bolts10 Nm (7 lb-ft)
13. 13

    Reconnect turbocharger oil drain and EGR
    Reinstall the turbocharger oil drain tube with new gaskets at both connections. Torque mounting bolts per factory specification. If EGR was removed, reconnect the EGR tube to the manifold and intake with new gaskets. Torque all connections properly.
14. 14

    Reconnect exhaust downpipe
    Raise the exhaust downpipe back into position at the manifold outlet or turbocharger connection. Install new gasket or v-band clamp as applicable. Torque all fasteners per factory specification. Ensure the exhaust system hangs properly without strain on connections.

Reassembly

1. Reinstall engine cover if equipped
2. Reconnect both battery negative terminals
3. Double-check all connections and torque values before starting engine

Verification

• Start the engine and allow it to idle. Listen carefully for any exhaust leaks at the manifold gasket area
• With engine at idle, use your hand near (not touching) the manifold flange to feel for escaping exhaust gases
• Bring engine to operating temperature and rev to 2000 RPM several times while listening for leaks
• Allow engine to fully heat cycle, then shut off and allow to cool. Re-check torque on all manifold nuts after first heat cycle—retorque if necessary
• Inspect for any signs of soot or discoloration around gasket area after first 100 miles of driving

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