Front Pipe

Procedure for removing and replacing the front exhaust pipes (catalytic converter outlet to center muffler connection) on a 2009 Aston Martin DB9 6.0L V12.

Warnings

Tools required

Parts

• Front pipe gaskets (catalytic converter to front pipe) × 2 — Use OEM specification
• Front pipe to center muffler gaskets × 2 — Use OEM specification
• Exhaust flange bolts/nuts × 1 — M8 or M10 flange hardware as needed

Preparation

1. Ensure exhaust system is completely cool (minimum 2 hours after engine operation)
2. Raise vehicle on lift or securely support on jack stands at all four corners with wheels removed for access
3. Apply penetrating oil to all visible exhaust flange bolts, hanger bolts, and oxygen sensor threads; allow to soak minimum 30 minutes
4. Verify replacement parts and gaskets are available before disassembly
5. Place magnetic trays for hardware organization (left bank and right bank separation recommended)

Procedure

1. 1

   Remove heat shields
   Locate and remove the exhaust heat shields covering the front pipe areas. These are typically secured with Torx or E-Torx fasteners to the underbody. Remove all heat shield fasteners (verify exact count and fastener type against OEM documentation) and carefully lower shields away from exhaust components. Inspect shields for damage and set aside for reinstallation.
2. 2

   Disconnect oxygen sensors - left bank
   Locate the oxygen sensor(s) associated with the left bank front pipe (verify exact number and pre-cat/post-cat location against OEM documentation). Disconnect the electrical connector by pressing the release tab and pulling apart. Using an oxygen sensor socket (size must be verified against OEM documentation — commonly 22mm / 7/8" but not confirmed for this platform), carefully loosen the sensor by turning counterclockwise. Remove sensor completely and set aside in a clean area to protect the sensor tip from contamination. If sensor is difficult to remove, allow the engine to reach a warm (not hot) temperature to aid removal, and apply penetrating oil only to the external bung threads away from the sensor tip. Use heat with extreme caution to avoid damaging wiring and surrounding components. Note: Using an oxygen sensor socket (verify 22mm or 7/8" hex size for this platform), carefully loosen the sensor by turning counterclockwise.
3. 3

   Disconnect oxygen sensors - right bank
   Repeat oxygen sensor removal procedure for the right bank front pipe post-catalytic converter sensor. Disconnect electrical connector, remove sensor with oxygen sensor socket, and protect sensor tip from contamination.
4. 4

   Support front pipes
   Position a transmission jack or have an assistant support the front pipes from below to prevent sudden dropping when fasteners are removed. The pipes are heavy and connected at multiple points; controlled support is essential to prevent damage to catalytic converters or surrounding components.
5. 5

   Remove front pipe to center muffler connection - left bank
   Locate the flange connection where the left bank front pipe connects to the center muffler section. Determine the joint type at the front pipe to center muffler connection (verify against OEM documentation — this platform commonly uses a spring-loaded ball-joint or clamp-style connection rather than a flat bolted flange). Remove the appropriate fasteners, noting exact count and head size. If bolts are seized, use penetrating oil and allow additional soak time. Once fasteners are removed, note the position of any alignment sleeves or spacers at the joint.
6. 6

   Remove front pipe to center muffler connection - right bank
   Repeat the flange disconnection procedure for the right bank front pipe to center muffler connection. Remove all flange bolts and note any alignment hardware present.
7. 7

   Disconnect exhaust hangers
   Locate the rubber exhaust hangers supporting the front pipes (verify exact hanger count against OEM documentation). Using a pry bar or by hand, carefully work the hanger loops off the mounting brackets. Spray rubber hangers with penetrating oil or soapy water to ease removal. Do not cut hangers unless replacement hangers are available.
8. 8

   Remove front pipe to catalytic converter connection - left bank
   Locate the connection between the left bank catalytic converter outlet and the front pipe inlet. Determine the joint type (bolted flange, spring-bolt, or clamp — verify against OEM documentation) and remove the appropriate fasteners, noting exact count and thread size. These fasteners are subject to high heat and corrosion; use penetrating oil liberally. Once loosened, separate the flange connection. A pry bar or exhaust separator tool may be needed to break the gasket seal.
9. 9

   Remove front pipe to catalytic converter connection - right bank
   Repeat the catalytic converter flange disconnection procedure for the right bank. Remove all flange bolts and separate the connection. With both ends disconnected, carefully lower the right bank front pipe from the vehicle while ensuring oxygen sensor wiring is clear.
10. 10

    Remove left bank front pipe
    With all connections released on the left bank, carefully maneuver the front pipe out from under the vehicle. Route the pipe past any cross-members or suspension components. The pipe may require rotation or angling to clear the chassis. Once removed, inspect the pipe for cracks, leaks, or excessive corrosion.
11. 11

    Clean flange surfaces and inspect hardware
    Using a wire brush, thoroughly clean all flange mating surfaces at the catalytic converter outlets and center muffler inlets. Remove all old gasket material and carbon deposits to ensure proper sealing. Inspect all flange studs and bolt holes for damage or stripped threads. Inspect rubber exhaust hangers for tears or degradation; replace if damaged. Check oxygen sensor bungs in the new or existing pipes for thread damage.
12. 12

    Prepare new front pipes for installation
    Install new gaskets on the catalytic converter outlet flanges and center muffler inlet flanges. Apply a thin coat of anti-seize compound to all exhaust flange bolt threads (not the flange faces). If reusing oxygen sensors, apply a thin coat of anti-seize to the sensor threads only, keeping anti-seize away from the sensor tip to prevent contamination.
13. 13

    Install left bank front pipe
    With assistance or using a transmission jack for support, position the left bank front pipe into place. Align the pipe inlet flange with the catalytic converter outlet flange and start 1-2 bolts finger-tight to hold position. Then align the rear flange with the center muffler connection and start those bolts finger-tight. Do not fully tighten any connections yet.
14. 14

    Install right bank front pipe
    Position the right bank front pipe similarly to the left bank. Start all flange bolts at both the catalytic converter connection and center muffler connection finger-tight. Ensure pipes are properly seated and flanges are flush before proceeding.
15. 15

    Attach exhaust hangers
    Reconnect all rubber exhaust hangers to their mounting brackets. Use soapy water or penetrating oil to ease installation. Ensure hangers are fully seated on the brackets and pipes are properly supported without binding or stress.
    Torque spec

    Hanger Bolts27 Nm (20 lb-ft)
16. 16

    Torque catalytic converter flange connections
    Beginning with the catalytic converter to front pipe flanges, torque all flange bolts in a cross-pattern to ensure even clamping force. Torque to specification using a calibrated torque wrench. Complete both left and right bank connections.
    Torque spec

    Exhaust Flange Bolt25 Nm (18 lb-ft)
17. 17

    Torque center muffler flange connections
    Torque the front pipe to center muffler flange bolts in a cross-pattern to specification. This ensures proper sealing and prevents exhaust leaks. Complete both left and right bank connections.
    Torque spec

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

    Install oxygen sensors
    Install the oxygen sensors into the front pipes for both banks. Apply anti-seize compound to the sensor threads only, avoiding the sensor tip. Thread sensors in by hand initially to prevent cross-threading, then tighten to specification using the oxygen sensor socket and torque wrench. Reconnect the electrical connectors for both sensors, ensuring they click securely into place.
    Torque spec

    O2 Sensor45 Nm (33 lb-ft)
19. 19

    Reinstall heat shields
    Position the heat shields back over the front pipes and align with mounting holes. Install all heat shield fasteners and torque to specification. Ensure shields do not contact exhaust pipes directly and have proper clearance.
    Torque spec

    Heat Shield Bolts10 Nm (7 lb-ft)

Reassembly

1. Final installation torque sequence: catalytic converter flanges first, then center muffler flanges, then hanger bolts, then heat shields
2. Ensure all oxygen sensor electrical connectors are properly secured and wiring is routed away from hot exhaust components
3. Verify all flange connections are flush and gaskets are properly seated before final torque
4. Double-check that no tools or parts have been left in the work area under the vehicle

Verification

• Lower vehicle and start engine; allow to idle and listen for exhaust leaks at all flange connections
• With engine at operating temperature, carefully inspect all connections for signs of leaking (soot deposits, hissing sounds, or exhaust smell)
• Verify oxygen sensor readiness using an OBD-II scanner; sensors should show activity within 2-3 minutes of engine start
• Perform a test drive and listen for any rattles, vibrations, or unusual exhaust notes indicating loose components
• Re-inspect all flange connections after first 50-100 miles of driving and re-torque if necessary

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