Oil Separator/PCV

Replace the oil separator (PCV system) on the 2009 Aston Martin DB9 6.0L V12, which requires removing engine covers, disconnecting breather hoses, and accessing the separator mounted on the valve cover area.

Warnings

Tools required

Parts

• Oil separator (PCV valve assembly) × 1 — Use OEM specification
• Oil separator gasket/seal × 1 — Use OEM specification
• Breather hose O-rings (if degraded) × 2 — Use OEM specification

Preparation

1. Ensure engine is completely cool to the touch
2. Open hood and secure in raised position
3. Disconnect negative battery terminal to prevent electrical issues
4. Place catch pan and absorbent material under work area
5. Take photos of hose routing and connections before disassembly for reference

Procedure

1. 1

   Remove engine cover assembly
   Locate and remove the engine cover fasteners. The DB9 V12 engine cover fasteners should be identified and their type/count confirmed against Aston Martin service documentation for the 2009 model year before removal. Remove all fasteners, then lift the cover assembly straight up to disengage any locating grommets. Set aside in a clean area. Note: The DB9 V12 engine cover fastener type and count should be verified against OEM documentation before removal; configurations vary and may use Torx or push-type fasteners. Note: The DB9 V12 engine covers are secured by Torx fasteners; verify the exact fastener type, size, and count against factory documentation before removal. Note: Fastener count and type unverified — confirm against Aston Martin service documentation (may be Torx or push-type)
2. 2

   Remove secondary trim panels and air intake components
   Remove any secondary plastic engine bay trim panels that obstruct access to the rear valve cover area. These are typically secured with T25 or T30 Torx fasteners. If necessary, disconnect the air intake ducting by loosening hose clamps and removing any T25 fasteners securing intake resonator boxes or ducts. Move components aside to create workspace.
3. 3

   Locate the oil separator assembly
   The oil separator location on the DB9 V12 must be confirmed against factory service documentation. It is commonly integrated into or mounted near a valve cover/crankcase breather area; verify exact position before planning access. It is a cylindrical or rectangular black plastic component with multiple breather hoses connected to it. Identify the separator and trace all connected hoses. Confirm the actual hose count and routing against Aston Martin service documentation for the 2009 DB9 6.0L V12 before disconnecting anything; do not rely on a generic configuration.
4. 4

   Disconnect breather hoses from oil separator
   Working from the most accessible hose first, carefully release the spring clamps or squeeze-type hose clamps securing each breather hose to the oil separator. Use needle-nose pliers to compress and slide spring clamps back along the hose. Once clamps are moved, twist and pull each hose off the separator nipples. Expect some residual oil to drain; have rags ready. Disconnect all hoses connected to the separator body.
5. 5

   Disconnect oil separator mounting fasteners
   Locate the mounting fasteners securing the oil separator to the valve cover or engine mounting bracket. The number, type, and size of the oil separator mounting fasteners must be confirmed against OEM documentation for the 2009 DB9 6.0L V12 before removal. Remove all mounting fasteners and carefully extract the oil separator from its mounting location. Be prepared for residual oil to spill from the unit—keep the catch pan positioned below. Note: Remove the oil separator mounting fasteners (verify exact count, type, and size against Aston Martin service documentation for the 2009 DB9 6.0L V12 before proceeding). Note: Verify the exact mounting fastener count, type, and size against factory service documentation before removal; do not assume a specific head type. Note: Fastener count, type, and size unverified — confirm against Aston Martin service documentation for the 2009 DB9 6.0L V12 before removal
6. 6

   Remove old gasket and clean mounting surface
   Once the oil separator is removed, inspect the mounting surface on the valve cover or engine. Remove the old gasket or O-ring seal completely, using a plastic scraper if necessary to avoid scratching the sealing surface. Clean the mounting surface thoroughly with brake cleaner and a clean rag to ensure proper sealing for the new separator. Inspect for any damage or excessive wear.
7. 7

   Inspect breather hoses and connections
   With the separator removed, inspect all breather hoses for cracks, splits, or oil saturation that would indicate deterioration. Check the hose connection nipples on the valve cover and intake manifold for damage. Replace any hoses or O-rings that show signs of wear. Clean hose connection points with brake cleaner.
8. 8

   Install new oil separator gasket
   Place the new gasket or O-ring seal onto the mounting surface of the new oil separator. Ensure the gasket is properly seated in its groove and oriented correctly according to OEM installation guidelines. Do not use sealant unless specifically required by the manufacturer.
9. 9

   Install new oil separator assembly
   Position the new oil separator into the mounting location, aligning the mounting holes with the valve cover or bracket. Install the mounting fasteners hand-tight first to ensure proper alignment, then tighten progressively in a cross-pattern to ensure even gasket compression. Tighten the mounting fasteners to the OEM-specified torque for the 2009 DB9 6.0L V12 oil separator (verify exact value in Aston Martin service documentation; these are low-torque fasteners threading into aluminum and must not be over-tightened). Note: Tighten the mounting fasteners to the OEM-specified torque value (verify against factory documentation for the 2009 DB9 6.0L V12). These thread into aluminum and must not be overtightened. Note: Tighten the mounting fasteners to the factory-specified torque (verify against Aston Martin service data before final tightening); these thread into aluminum and must not be over-torqued. Note: Torque value unverified — confirm against Aston Martin service documentation for the 2009 DB9 6.0L V12 (low-torque fasteners into aluminum)
10. 10

    Reconnect breather hoses
    Reconnect each breather hose to the appropriate nipple on the new oil separator, referencing your earlier photos. Ensure each hose is fully seated onto its nipple (you should feel it bottom out). Slide the spring clamps or hose clamps back into position over the connection point to secure each hose. Verify all connections are tight and properly positioned.
11. 11

    Reinstall air intake components and trim panels
    Reinstall any air intake ducting, resonator boxes, or secondary trim panels that were removed for access. Secure all components with their original T25 or T30 Torx fasteners and ensure hose clamps on intake ducting are properly tightened.
12. 12

    Reinstall engine cover
    Position the main engine cover back onto the engine, aligning any locating grommets. Install all T30 Torx fasteners around the perimeter and tighten evenly. Ensure the cover sits flush and is properly secured.
13. 13

    Reconnect battery and clear any fault codes
    Reconnect the negative battery terminal. Using an appropriate diagnostic tool (Aston Martin AMDS or a capable scan tool), clear any fault codes related to the PCV/crankcase ventilation system that may have been stored. Start the engine and allow it to idle to verify proper operation. Note: If fault codes were stored (e.g., from battery disconnection), use an appropriate Aston Martin-compatible diagnostic tool to read and clear them. Note that a generic OBD-II scanner may not fully communicate with the DB9's manufacturer-specific control modules. Note: If a compatible diagnostic tool (Aston Martin AMDS or equivalent generic OBD-II scanner) is available, scan for and clear any stored fault codes related to engine ventilation or emissions that may have been triggered during the procedure.

Reassembly

1. Reassembly follows removal in reverse order
2. Ensure all breather hose connections are secure and clamps are properly positioned
3. Verify no tools or rags are left in the engine bay before closing the hood
4. Double-check that all fasteners for engine covers and trim panels are reinstalled

Verification

• Start the engine and let it idle for 2-3 minutes, listening for any unusual hissing or vacuum leaks from the PCV system area
• Check for oil leaks around the oil separator mounting area and all hose connections
• Rev the engine gently to 2000-3000 RPM and verify smooth operation with no rough idle or stumbling
• Inspect for any fault codes related to the PCV or crankcase ventilation system
• After a short test drive, re-inspect all connections for leaks or loose hoses

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