Intermediate Pipe

This procedure covers removal and installation of the intermediate exhaust pipe on a 2009 Aston Martin DB9 6.0L V12, connecting the catalytic converters to the rear muffler section.

Warnings

Tools required

Parts

• Intermediate pipe gaskets (set of 2) × 1 — Use OEM specification
• Exhaust flange nuts/bolts (if corroded) × 1 — M10 flange hardware
• Exhaust hangers/isolators (if deteriorated) × 1 — Rubber exhaust mounts

Preparation

1. Ensure exhaust system is completely cool to the touch (wait at least 2 hours after engine operation)
2. Raise vehicle on lift or support securely on jack stands at manufacturer-specified lift points
3. Spray all exhaust flange bolts, hanger bolts, and O2 sensor threads with penetrating oil and allow 15-20 minutes to soak
4. Inspect intermediate pipe routing and note locations of heat shields and mounting points
5. Have replacement gaskets and anti-seize compound ready before disassembly

Procedure

1. 1

   Disconnect oxygen sensors
   Locate any oxygen sensors mounted in the intermediate pipe section (confirm sensor locations against OEM documentation, as some sensors may be upstream at the catalytic converters). Disconnect the electrical connectors by releasing the locking tabs and pulling directly away from the sensor body. Using an O2 sensor socket of the correct size for this application (commonly 22mm — verify against OEM documentation), carefully unthread each sensor by turning counterclockwise. Do not force; apply additional penetrating oil if resistance is excessive. Remove sensors completely and set aside in a clean location to prevent contamination of sensor elements. Note: Using an O2 sensor socket (verify 22mm or 7/8" for this application), carefully unthread each sensor located in the intermediate pipe section by turning counterclockwise. Note: Using the appropriate O2 sensor socket (commonly 22mm / 7/8"), carefully unthread each sensor by turning counterclockwise. Note: the V12 uses multiple O2 sensors across both banks (verify exact count and location against OEM documentation for the 2009 DB9 6.0L V12); confirm which sensors are mounted in or adjacent to the intermediate pipe section before removal.
2. 2

   Remove heat shields
   Identify heat shields covering or adjacent to the intermediate pipe. Remove the fasteners securing each heat shield section. Expect Torx or E-Torx fasteners typical of Aston Martin chassis components. Carefully lower heat shields away from the pipe, noting their orientation and any alignment tabs for reassembly. Inspect shields for damage or excessive corrosion. Note: Install and tighten heat shield fasteners to the OEM specification (small-diameter low-torque hardware — verify exact size and torque value against OEM documentation for the 2009 DB9 6.0L V12).
3. 3

   Disconnect front flange from catalytic converters
   Locate the front flange connection where the intermediate pipe mates to the catalytic converter outlets. This connection uses a dual-outlet flange with spring-loaded bolts or nuts. Support the intermediate pipe weight with one hand or a suitable stand. Remove the flange fasteners (verify exact count against manufacturer documentation; dual-outlet V12 configuration). Once fasteners are removed, carefully separate the flange joint. If gaskets are stuck, use a plastic scraper to break the seal without damaging flange surfaces. Note: Remove the flange fasteners (count and specification per OEM documentation for this dual-outlet V12 configuration — verify before ordering hardware). Note: Remove the flange fasteners (verify exact count against OEM documentation for the 2009 DB9 6.0L V12 before proceeding).
4. 4

   Disconnect rear flange from muffler assembly
   Move to the rear of the intermediate pipe where it connects to the main muffler section. Support the pipe to prevent it from falling when disconnected. Remove the rear flange fasteners (count and joint type per OEM documentation — verify before beginning). Gently work the joint apart, using slight rotation if needed to break any corrosion bond. Avoid prying directly on flange surfaces. Note: Remove the rear flange fasteners (verify exact count and joint type — flange vs. slip joint — against manufacturer documentation). Note: Remove the rear flange fasteners (verify exact count and joint type against OEM documentation for the 2009 DB9 6.0L V12 before proceeding).
5. 5

   Release exhaust hangers
   The intermediate pipe is supported by rubber isolator hangers at 2-3 points along its length. Using an exhaust hanger removal tool or carefully with a pry bar, compress each rubber isolator and slide the pipe hook out of the hanger bracket. Work systematically from front to rear or vice versa. Note the orientation of each hanger for reinstallation.
6. 6

   Remove intermediate pipe assembly
   With all fasteners and hangers disconnected, carefully lower the intermediate pipe assembly from the vehicle. The pipe is heavy and may require two people due to the V12 configuration creating a wide, dual-pipe assembly. Maneuver the pipe around any chassis cross-members or suspension components, rotating as needed. Place on a clean work surface for inspection.
7. 7

   Inspect and clean mating surfaces
   With the intermediate pipe removed, inspect all flange surfaces on both the catalytic converters and rear muffler section for damage, warping, or excessive corrosion. Use a wire brush to clean all mating surfaces, removing old gasket material and carbon deposits. Inspect the flange faces for flatness; any warping may cause exhaust leaks. Check rubber hanger isolators for cracking or deterioration and replace if necessary.
8. 8

   Prepare new intermediate pipe
   If installing a new intermediate pipe, verify it matches the removed component in length, flange configuration, O2 sensor bung locations, and hanger positions. Apply a light coat of anti-seize compound to the threads of the O2 sensor bungs (being careful to keep anti-seize away from the sensor elements). Place new gaskets on each flange connection that requires one (verify quantity and which joints are gasketed against OEM documentation for the 2009 DB9 6.0L V12), ensuring they are properly seated in any locating grooves.
9. 9

   Position intermediate pipe and engage hangers
   With assistance, lift the intermediate pipe into position under the vehicle. Align the pipe with the rubber hanger isolators and engage the pipe hooks into each hanger bracket. Use an exhaust hanger tool or lubricate the rubber isolators with soapy water to ease installation. Do not fully seat all hangers yet; leave slight play for alignment of flange connections.
10. 10

    Connect front flange to catalytic converters
    Align the front flange of the intermediate pipe with the catalytic converter outlet flanges. Ensure gaskets are properly positioned between mating surfaces. Insert flange bolts/studs and hand-thread nuts until finger-tight. Do not torque at this stage. Verify alignment by checking that flanges mate evenly without gaps on either side.
11. 11

    Connect rear flange to muffler assembly
    Align the rear flange of the intermediate pipe with the main muffler section inlet. Position the gasket if the rear joint is a flanged connection (confirm joint type against manufacturer documentation — flanged connections require a gasket, true slip-fit joints do not). Insert flange bolts and hand-thread nuts until finger-tight. Check alignment across the entire exhaust system from catalytic converters to mufflers, ensuring no binding or misalignment. Adjust hanger positions as needed.
12. 12

    Torque front flange connection
    Using a torque wrench, tighten the front flange bolts connecting to the catalytic converters in a cross-pattern to ensure even loading. Apply anti-seize to threads only if the manufacturer torque specification accounts for lubricated fasteners; otherwise torque dry to spec to avoid over-tightening. Torque each bolt to the manufacturer-specified value for the intermediate pipe front flange (verify exact spec in service documentation). Recheck torque after completing the pattern to ensure no loosening occurred. Note: Torque each bolt to the OEM specification for the 2009 DB9 V12 exhaust flange hardware. Only use anti-seize if the OEM procedure permits, and adjust torque accordingly since lubricated threads reach target preload at lower torque than dry threads.
    Torque spec

    Exhaust Flange Bolt25 Nm (18 lb-ft)
13. 13

    Torque rear flange connection
    Using a torque wrench, tighten the rear flange bolts connecting to the muffler assembly in a cross-pattern. Torque each bolt to the OEM specification for the 2009 DB9 V12 rear exhaust flange hardware. Only use anti-seize if the OEM procedure permits, and adjust torque accordingly since lubricated threads reach target preload at lower torque than dry threads. The exhaust system should now be rigidly connected at both ends.
    Torque spec

    Exhaust Flange Bolt25 Nm (18 lb-ft)
14. 14

    Fully seat exhaust hangers
    Now that flanges are torqued and alignment is final, ensure all rubber hanger isolators are fully seated with pipe hooks completely engaged in brackets. The pipe should hang naturally without stress or binding. Inspect clearance around the pipe, verifying adequate spacing from chassis components, suspension, and body panels (minimum 10-15mm clearance).
15. 15

    Install oxygen sensors
    Apply a small amount of anti-seize compound to the threads of each oxygen sensor, being extremely careful to keep anti-seize away from the sensor tip and element (contamination will destroy the sensor). Thread each sensor into its bung by hand to ensure proper alignment and prevent cross-threading. Once hand-tight, use the O2 sensor socket to torque to the manufacturer-specified value (verify exact spec; note many sensors ship with pre-applied thread coating and require no additional anti-seize). Reconnect the electrical connectors, ensuring locking tabs are fully engaged.
    Torque spec

    O2 Sensor45 Nm (33 lb-ft)
16. 16

    Reinstall heat shields
    Position heat shields in their original locations, aligning any locating tabs or offset holes. Install and tighten heat shield fasteners to specification. Ensure shields do not contact the exhaust pipe directly (some designs include standoffs or locating clips). Verify shields are secure and will not vibrate or rattle.
    Torque spec

    Heat Shield Bolts10 Nm (7 lb-ft)

Reassembly

1. Verify all fasteners are torqued to specification and no tools or parts have been left in the work area
2. Perform a final visual inspection of all connections, hangers, and clearances before lowering vehicle
3. Do not apply excessive force if components do not align easily; misalignment indicates incorrect hanger positioning or component fitment

Verification

• Start the engine and allow it to reach operating temperature while monitoring for exhaust leaks at all flange connections
• Listen for unusual exhaust noise, rattles, or hissing sounds that would indicate a leak or loose component
• Check O2 sensor operation using a diagnostic scan tool; verify no fault codes are present for sensor circuit or performance
• Perform a test drive and listen for any contact between exhaust components and chassis/body, especially over bumps
• After the first 50-100 miles of operation, re-inspect all flange connections for any signs of loosening or exhaust staining indicating leaks

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