Valve Spring - Single

This procedure guides you through the removal and replacement of a single valve spring on the 2009 Aston Martin DB9 6.0L V12 engine, requiring significant disassembly to access the cylinder head components.

Warnings

Tools required

Parts

• Valve spring (specify cylinder and intake/exhaust) × 1 — Use OEM Aston Martin specification
• Valve spring retainer/keeper set × 1 — Use OEM specification
• Valve cover gasket(s) × 1 — Use OEM specification
• Spark plug tube seals × 1 — Use OEM specification
• Coolant (OAT 50/50 premixed) × 1 — Use OEM specification
• Engine oil and filter × 1 — Use OEM specification
• Anti-seize compound × 1 — Use copper or nickel-based

Fluids

• 5W-30 engine oil — 10.5 qt
• OAT 50/50 coolant — 10.5 qt

Preparation

1. Park vehicle on level ground and engage parking brake. Ensure engine is completely cold.
2. Disconnect negative battery terminal and isolate the cable.
3. Remove engine cover(s) - typically secured with quick-release fasteners or Torx bolts.
4. Relieve fuel system pressure by removing the fuel pump fuse and cranking the engine until it stalls.
5. Drain coolant from the radiator and engine block into appropriate containers. Note total quantity for refill verification.
6. Document or photograph all electrical connections, vacuum lines, and hose routing before disassembly.
7. Identify the specific cylinder and valve (intake or exhaust) requiring the spring replacement. Mark clearly to avoid confusion.

Procedure

1. 1

   Remove intake plenum and throttle bodies
   Remove the air intake ducting and airbox assembly. Disconnect the throttle body electrical connector(s) — verify the number and location of throttle bodies against Aston Martin service data for this engine. Remove the intake plenum - this will involve removing multiple Torx fasteners securing the plenum to the intake manifold runners. Disconnect any vacuum lines, PCV connections, and breather hoses attached to the plenum. The DB9 V12 uses a complex intake system; work methodically and label all connections. Remove the throttle bodies if necessary for access to the valve covers on the affected bank.
2. 2

   Remove ignition coils and spark plugs
   Remove the ignition coil pack from the affected cylinder by disconnecting the electrical connector and removing the mounting fastener (typically a single Torx bolt per coil). Remove the spark plug from the affected cylinder using the appropriate spark plug socket. Inspect the plug condition while out - this can indicate valve or combustion issues that may have caused spring failure. Note: Spark plug socket (confirm exact hex size — commonly 14mm or 16mm — against Aston Martin service data for this engine)
   Torque spec

   Spark Plugs - Aluminum Head15 Nm (11 lb-ft)
3. 3

   Remove valve cover from affected bank
   Disconnect any remaining electrical connectors, breather hoses, or PCV lines attached to the valve cover. Remove the valve cover mounting bolts - these are typically 10mm head bolts torqued to specification, arranged around the perimeter of the cover. Note the bolt locations as some may be different lengths. Carefully lift the valve cover away from the cylinder head. If it resists, gently tap with a rubber mallet - do not pry against the aluminum head surface. Remove and inspect the valve cover gasket.
4. 4

   Identify and access the affected valve
   With the valve cover removed, identify the specific valve requiring spring replacement. The DB9 6.0L V12 uses dual overhead camshafts (DOHC) with 4 valves per cylinder. Determine whether the affected valve is intake or exhaust, and its position within the cylinder. Rotate the engine crankshaft using a breaker bar on the front crankshaft pulley bolt (normal direction of rotation — verify clockwise-when-viewed-from-front against Aston Martin service data) to position the affected valve's cam lobe pointing away from the valve (valve fully closed with no cam pressure). This is critical for safe spring removal.
5. 5

   Remove rocker arm or finger follower
   The DB9 V12 uses roller finger followers pivoting on hydraulic lash adjusters rather than bolted rocker arms. With the cam lobe rotated away (valve closed, no cam pressure), the follower can be released from the valve stem tip and lash adjuster. On this engine the camshaft carrier/cap or camshaft itself may need to be loosened to release follower tension before the follower can be lifted off — verify the exact retention method and any camshaft removal requirement against Aston Martin service data. Do NOT expect individual per-follower bolts. Carefully lift the finger follower away, note its orientation, and store in a clean, organized location. Inspect the follower roller and contact surfaces for wear or scoring.ring.
   Torque spec

   Rocker Arm Bolts30 Nm (22 lb-ft)
6. 6

   Install valve spring compressor
   Select the appropriate adapters for your valve spring compressor tool to fit the DB9's valve configuration. Position the compressor tool over the affected valve, ensuring the lower foot seats firmly on the valve spring retainer and the upper portion engages the cylinder head or a secure mounting point. Double-check that the tool is centered and fully seated before applying any pressure. This engine uses aluminum heads - tool slippage will cause damage.
7. 7

   Compress valve spring and remove keepers
   Slowly compress the valve spring using the compressor tool until the valve spring retainer is depressed enough to release tension on the valve keepers (collets). The keepers are small tapered semi-circular pieces that lock the retainer to the valve stem. Use a magnetic pick-up tool to carefully remove both keepers. Place them immediately in a parts tray - they are easily lost. If the keepers are stuck, a gentle tap on the valve spring retainer with a small brass punch while under compression may help release them.
8. 8

   Remove valve spring and retainer
   With the keepers removed, slowly release pressure on the valve spring compressor tool. Remove the tool completely. Lift off the valve spring retainer (the upper cup that the keepers secured). Remove the valve spring itself. On this engine, there may be an inner and outer spring or a single spring with damper - note the configuration. Also remove any spring seats or shims beneath the spring. Inspect all components for damage, unusual wear patterns, or signs of overheating.
9. 9

   Inspect valve and valve seat
   With the spring removed, carefully inspect the valve stem for scoring, wear, or bending. Check the valve stem seal (if visible) for damage. Inspect the valve seat area in the combustion chamber for pitting or damage. Measure valve stem diameter if micrometers are available and compare to specifications. If the valve moves excessively or shows damage, additional repairs beyond spring replacement will be necessary. Do not allow the valve to drop into the cylinder - if concerned about valve control, apply compressed air to the spark plug hole to hold the valve in place with cylinder pressure.
10. 10

    Install new valve spring assembly
    Install any spring seats or shims in their original positions on the cylinder head. Install the new valve spring, ensuring correct orientation - if the spring has closer-wound coils on one end, typically the tighter end faces the cylinder head (verify with service data for this specific engine). Place the valve spring retainer over the valve stem and spring.
11. 11

    Compress new spring and install keepers
    Reinstall the valve spring compressor tool, ensuring proper seating on the new spring and retainer. Compress the spring until the valve stem grooves are exposed above the retainer. Apply a small amount of grease to the valve stem grooves to help hold the keepers in place during installation. Carefully position both keepers in the valve stem grooves using the magnetic pick-up tool, ensuring they seat properly in both the stem grooves and the retainer. Slowly and carefully release the compressor tool pressure while watching to ensure the keepers remain seated. Once pressure is released, give the valve spring retainer a light tap with a plastic tool to ensure the keepers are fully seated.
12. 12

    Reinstall finger follower
    Verify the camshaft is still positioned with the lobe pointing away from the valve. Apply a light coat of clean engine oil to the finger follower contact surfaces. Position the finger follower over the valve stem tip and onto the hydraulic lash adjuster, ensuring it seats correctly. If the camshaft carrier/cap or camshaft was loosened to release the follower, reinstall and torque those fasteners to the Aston Martin specified sequence and value. Do NOT expect individual per-follower bolts — verify the exact retention method against service data. The cam lobe must be pointing away during this installation to avoid preloading the valve.
    Torque spec

    Rocker Arm Bolts30 Nm (22 lb-ft)
13. 13

    Verify valve operation
    Manually rotate the engine crankshaft through at least two complete revolutions (720 degrees) while watching the repaired valve's operation. Verify smooth movement with no binding, unusual noise, or interference. Check that the valve fully closes and opens with cam rotation. Listen for any abnormal sounds that might indicate improper keeper seating or spring installation.
14. 14

    Clean and prepare valve cover mating surfaces
    Thoroughly clean the cylinder head valve cover mating surface using a plastic scraper and lint-free rags. Remove all old gasket material and oil residue. Clean the valve cover mating surface as well. Inspect both surfaces for damage, warping, or irregularities that could prevent proper sealing. The surfaces must be completely clean and dry before gasket installation.
15. 15

    Install valve cover
    Install a new valve cover gasket in the valve cover groove or on the cylinder head (depending on design - the DB9 typically uses a gasket that seats in the valve cover). Ensure the gasket is properly seated with no twists or misalignment. Carefully position the valve cover onto the cylinder head, aligning all mounting holes. Install all valve cover bolts hand-tight first, then torque in the OEM-specified sequence (verify the exact numbered pattern against Aston Martin service data) to specification. Reconnect all breather hoses, PCV connections, and electrical connectors to the valve cover.
    Torque spec

    Valve Cover Bolts10 Nm (7 lb-ft)
16. 16

    Reinstall spark plug and ignition coil
    Do not apply anti-seize to the spark plug threads unless specified by Aston Martin — modern plugs with plated threads are typically installed dry; anti-seize alters torque readings and can cause over-torque and thread damage in the aluminum head. Verify against service data before installing the plug and torque to specification. Install the spark plug and torque to specification using the spark plug socket and torque wrench. Install the ignition coil pack, ensuring proper seating in the spark plug tube. Torque the coil mounting fastener and reconnect the electrical connector. Note: Only apply anti-seize if specified by Aston Martin service data — many modern plated spark plugs require NO anti-seize on aluminum heads to avoid over-torque and thread damage. If specified, apply a thin coat to the threads only (avoid the electrode and insulator).
    Torque spec

    Spark Plugs - Aluminum Head15 Nm (11 lb-ft)
17. 17

    Reinstall intake system components
    Reinstall the throttle bodies (if removed) with new gaskets if necessary. Reconnect all electrical connections to the throttle bodies. Reinstall the intake plenum using new gaskets or O-rings as required, torquing all fasteners to specification. Reconnect all vacuum lines, PCV hoses, and breather connections according to your documentation from disassembly. Reinstall the airbox and intake ducting.
18. 18

    Refill fluids and reconnect battery
    Refill the cooling system with the coolant type specified by Aston Martin for this vehicle (verify chemistry against service data), premixed 50/50, to the proper level. Burp the cooling system according to manufacturer procedure to remove air pockets. Check engine oil level and top off if necessary (oil may have been lost during valve cover removal). Reinstall the fuel pump fuse. Reconnect the negative battery terminal. Reinstall all engine covers. Note: Container for coolant (verify total cooling system capacity against Aston Martin service data) Note: Refill the cooling system with the Aston Martin OEM-specified coolant (verify exact chemistry — OAT/HOAT — against factory service data) mixed 50/50 to the proper level.
19. 19

    Start engine and verify repair
    Start the engine and allow it to idle. Listen carefully for any unusual valve train noise, ticking, or abnormal sounds from the repaired cylinder. Monitor for oil leaks at the valve cover gasket. Check for coolant leaks at all disturbed connections. Allow the engine to reach operating temperature while monitoring coolant level and temperature gauge. Verify smooth idle and throttle response.

Reassembly

1. Reinstall components in reverse order of removal, using new gaskets and seals where specified.
2. Ensure all electrical connectors are fully seated and locked - use the tactile click as confirmation.
3. Double-check all fasteners are torqued to specification, particularly valve cover bolts and rocker arm bolts.
4. Verify all vacuum lines and breather hoses are properly routed and secured to prevent vacuum leaks.

Verification

• Start the engine and listen for smooth, quiet valve train operation with no ticking or unusual noises from the repaired area.
• Verify no oil leaks from the valve cover gasket after the engine reaches operating temperature.
• Confirm no coolant leaks from any disturbed cooling system connections.
• Test drive the vehicle and verify smooth acceleration and normal engine performance with no misfires or hesitation.
• Re-check valve cover bolt torque and coolant level after the first heat cycle (cold engine check).

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

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