PCV Valve

This procedure guides you through locating and replacing the PCV valve on the 2009 Aston Martin DB9's 6.0L V12 engine, which typically requires accessing the valve covers and intake area.

Warnings

Tools required

Parts

• PCV valve × 1 — Use OEM Aston Martin specification
• PCV valve grommet (if damaged) × 1 — Use OEM specification

Preparation

1. Park vehicle on level ground and engage parking brake
2. Turn off ignition and remove key
3. Allow engine to cool completely (minimum 2 hours after operation)
4. Open hood and secure with prop rod
5. Disconnect negative battery terminal to prevent accidental electrical contact

Procedure

1. 1

   Access the Engine Bay and Identify PCV Valve Location
   The DB9 6.0L V12 does not use a conventional plug-in PCV valve; its crankcase ventilation is handled by oil separator/breather components integrated into the cam covers and intake breather routing. Before proceeding, confirm against Aston Martin workshop documentation whether any discrete serviceable PCV valve exists on this engine, as this job may instead require servicing breather hoses or oil separator components. Consult Aston Martin workshop documentation to confirm whether a serviceable PCV valve exists on this engine and its exact location before proceeding. Use your work light to inspect the valve cover and intake breather hose routing. Note: The crankcase ventilation layout on the DB9 6.0L V12 must be confirmed against Aston Martin service documentation before proceeding. The V12 uses an oil separator/breather arrangement, and a conventional serviceable PCV valve may not be present or may differ significantly from the generic location described here.
2. 2

   Remove Engine Cover Panels
   Remove the decorative engine cover(s) by locating and removing the securing fasteners. Verify the exact fastener type and count against Aston Martin workshop documentation before removal. Carefully lift the cover straight up to disengage any rubber mounting grommets. Set the cover aside in a clean area.
3. 3

   Disconnect Vacuum Hose from PCV Valve
   Trace the vacuum hose connected to the PCV valve. Note its routing and any clips or mounting points along the way. Gently twist and pull the vacuum hose off the PCV valve nipple. If the hose is stiff or stuck, use a small flathead screwdriver to carefully pry between the hose and valve nipple, working around the circumference. Inspect the hose end for cracks or damage.
4. 4

   Remove Any Obstructing Components
   Depending on exact PCV valve location, you may need to disconnect or move aside additional vacuum lines, wiring harnesses, or bracketry to access the valve. Use needle-nose pliers to release any spring clips securing nearby hoses. Tag or photograph wire routing if any connectors must be disconnected. Create enough working clearance to extract the PCV valve.
5. 5

   Extract the PCV Valve
   If the PCV valve is a press-fit type in a grommet, grasp the valve body firmly and pull straight out with a twisting motion. You may need to use needle-nose pliers for grip if space is limited. If the valve is threaded into the valve cover, rotate counterclockwise to unscrew. Some oil vapor residue is normal. Have shop towels ready to catch any drips. Inspect the grommet or mounting point for damage or deterioration.
6. 6

   Inspect Mounting Grommet and Valve Cover Port
   Examine the rubber grommet (if equipped) for cracks, hardening, or tears. A damaged grommet will cause vacuum leaks and must be replaced. Clean the valve cover port opening with a shop towel to remove any oil residue or debris. Ensure no dirt or contaminants can enter the valve cover opening. If replacing the grommet, carefully pry out the old grommet with a flathead screwdriver and press the new one into place until fully seated.
7. 7

   Prepare and Install New PCV Valve
   Remove the new PCV valve from packaging and verify it matches the old valve in configuration and connector type. If the serviced component is a conventional check-valve PCV, you may shake it and listen for the internal check valve to rattle, but note that the DB9 V12 breather/oil-separator components may not contain a rattling check valve. Verify the expected behavior against Aston Martin documentation before judging the part. If the valve threads into the valve cover, apply a light coat of clean engine oil to the threads. If it's a press-fit design, ensure the grommet is properly seated in the valve cover first.
   Torque spec

   PCV Valve8 Nm (6 lb-ft)
8. 8

   Install PCV Valve into Valve Cover
   For press-fit valves, align the valve with the grommet opening and push firmly with a twisting motion until fully seated and flush with the valve cover surface. For threaded valves, thread the valve in by hand clockwise until hand-tight, then torque to the value specified in Aston Martin service documentation. Do not apply a generic torque figure, as the correct spec for this engine has not been confirmed. Do not overtighten as this can crack the valve body or damage the valve cover threads. Verify the valve is secure and properly oriented for hose connection. Note: For threaded valves, thread the valve in by hand clockwise until hand-tight, then snug to the manufacturer-specified torque (verify against Aston Martin workshop documentation) using a socket or wrench. Note: For threaded valves, thread the valve in by hand clockwise until hand-tight, then snug to the OEM-specified torque (verify against Aston Martin workshop documentation) using a socket or wrench.
   Torque spec

   PCV Valve8 Nm (6 lb-ft)
9. 9

   Reconnect Vacuum Hose
   Push the vacuum hose firmly onto the PCV valve nipple until it seats completely. You should feel or hear a slight click as the hose seats. Tug gently on the hose to confirm it's secure. If the hose was damaged or excessively soft, replace it with new vacuum hose of the correct diameter. Reinstall any hose clips or retainers that secure the hose routing.
10. 10

    Reinstall Obstructing Components
    Reconnect any vacuum lines, wiring harnesses, or brackets that were moved or disconnected during access. Reference your photos to ensure correct routing. Secure all clips and fasteners. Verify no hoses are kinked and wiring is not pinched or stretched.
11. 11

    Reinstall Engine Cover
    Position the decorative engine cover over the engine, aligning rubber grommets with their mounting posts. Press down firmly to seat all grommets. Install and tighten the cover fasteners (verify exact type and count against Aston Martin documentation) in a crossing pattern to ensure even seating. Do not overtighten plastic fasteners.
12. 12

    Reconnect Battery and Perform System Check
    Reconnect the negative battery terminal and tighten securely. Start the engine and allow it to idle. Listen for any unusual vacuum leaks (hissing sounds) around the PCV valve area. Monitor idle quality; it should be smooth and steady. Rev the engine gently to 2000-2500 RPM and verify no vacuum leaks develop under increased airflow.

Reassembly

1. Ensure all vacuum hoses are properly routed and secured with clips
2. Verify the PCV valve is fully seated and all connections are tight
3. Double-check that no tools or shop towels were left in the engine bay
4. Confirm the engine cover is properly seated and all fasteners are installed

Verification

• Start engine and verify smooth idle with no hunting or roughness
• Listen carefully for any hissing sounds indicating vacuum leaks around the PCV valve area
• With engine at operating temperature, remove oil filler cap briefly; you should feel slight vacuum (cap should be slightly difficult to remove)
• Check for oil leaks around the PCV valve grommet or mounting point after a short test drive
• Monitor engine performance over the next few days for any check engine lights related to fuel trim or airflow

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