Head Gaskets - Both

Complete replacement of both cylinder head gaskets on the 6.0L V12 engine, including timing chain removal, camshaft removal, and cylinder head R&R.

Warnings

Tools required

Parts

• Cylinder head gasket (left bank) × 1 — Use OEM specification
• Cylinder head gasket (right bank) × 1 — Use OEM specification
• Valve cover gasket set (both banks) × 2 — Use OEM specification
• Timing cover gasket × 1 — Use OEM specification
• Timing chain tensioner gaskets × 4 — Use OEM specification
• Water pump gasket × 1 — Use OEM specification
• Thermostat housing gasket × 1 — Use OEM specification
• Intake manifold gaskets × 2 — Use OEM specification
• Exhaust manifold gaskets (both banks) × 2 — Use OEM specification
• Cylinder head bolt set (TTY bolts) × 1 — Use OEM specification
• Oil drain plug crush washer × 1 — Use OEM specification
• Spark plugs (set of 12) × 12 — Use OEM specification
• Engine oil 5W-30 × 11 — Use OEM approved specification
• Engine coolant OAT 50/50 × 11 — Use OEM specification
• Camshaft seal set × 4 — Use OEM specification
• Crankshaft front seal × 1 — Use OEM specification
• Various O-rings and seals for coolant pipes × 1 — Use OEM specification

Fluids

• engine_oil — 10.5 qt
• coolant — 10.5 qt

Preparation

1. Park vehicle on level surface and engage parking brake.
2. Disconnect negative battery terminal and wait 15 minutes for airbag system capacitor discharge.
3. Remove engine covers and acoustic panels from top of engine bay.
4. Document all wiring harness routing with photos, paying special attention to coil pack and injector connections.
5. Label all coolant hoses, vacuum lines, and breather hoses with tape flags indicating their connection points.
6. Place fender covers to protect paintwork during extended repair.
7. Ensure you have a complete set of OEM special tools including crankshaft locking tool and camshaft alignment pins specific to Aston Martin V12.

Procedure

1. 1

   Drain fluids and remove cooling system components
   Drain engine coolant from radiator petcock and engine block drain plugs into appropriate container. Remove coolant expansion tank after disconnecting hoses. Drain engine oil and remove oil filter. Remove radiator, cooling fans, and upper radiator hoses to provide working access. Disconnect heater hoses from firewall connections. Remove thermostat housing and thermostat.
2. 2

   Remove intake system and fuel components
   Remove engine air intake ducting and airbox assembly. Relieve fuel system pressure by removing fuel pump fuse and cranking engine briefly. Disconnect fuel supply and return lines at fuel rail connections using appropriate quick-disconnect tools. Remove throttle body and disconnect all vacuum lines from intake plenum. Remove intake manifold assembly in sections, starting with upper plenum then lower manifold runners. Each bank's intake manifold is secured with fasteners requiring Torx drivers. Disconnect all injector electrical connectors and label each by cylinder number.
3. 3

   Remove ignition system and valve covers
   Disconnect all 12 ignition coil connectors. Remove ignition coils from spark plug wells - each coil is secured with a single bolt. Remove spark plugs from all cylinders and store in order. Remove valve cover fasteners from both banks and carefully lift valve covers, noting breather hose connections. The valve covers have integrated PCV systems that must be carefully disconnected.
4. 4

   Remove exhaust manifolds
   Working from underneath vehicle (raise and support on jack stands), disconnect exhaust system at catalytic converter flanges. Remove heat shields from exhaust manifolds. Remove exhaust manifold mounting nuts from both banks. Verify the exact number of exhaust manifold studs/nuts per bank against the Aston Martin factory service manual before removal. Carefully extract manifolds, noting that space is extremely tight against chassis and steering components on right bank. Note: Confirm the exact number of exhaust manifold studs/nuts per bank against the Aston Martin factory service manual before removal.
5. 5

   Remove accessory drive system
   Remove serpentine belt by releasing tensioner. Remove power steering pump and secure aside without disconnecting hydraulic lines. Remove alternator and secure aside. Remove A/C compressor mounting bolts and secure compressor aside without disconnecting refrigerant lines - support with wire to prevent strain on hoses. Remove any remaining accessory brackets that interfere with timing cover access.
6. 6

   Remove crankshaft pulley and timing cover
   Lock crankshaft using Aston Martin special locking tool inserted through bellhousing access hole. Remove the crankshaft pulley bolt using a breaker bar or impact wrench - verify the exact removal/installation torque and whether this is a torque-to-yield bolt in the Aston Martin factory service manual before reassembly. Use harmonic balancer puller to remove crankshaft pulley from snout. Remove timing cover bolts following the loosening sequence (reverse of tightening). The timing cover has multiple bolt lengths - note locations for reassembly. Carefully pry timing cover away from engine block, being careful not to damage sealing surfaces. Remove timing cover gasket and inspect for oil leaks that may indicate additional seal replacement needs. Note: Remove crankshaft pulley bolt using breaker bar or impact wrench - this bolt is torqued to a high value (verify exact torque and TTY/angle requirement against Aston Martin factory service manual) and may require significant force. Note: Remove crankshaft pulley bolt using breaker bar or impact wrench - this bolt is torqued to the Aston Martin factory specification (verify exact value and whether it is a torque-plus-angle TTY fastener) and may require significant force.
7. 7

   Verify timing marks and lock timing components
   Rotate crankshaft to TDC cylinder 1 using crankshaft locking tool. Verify all timing marks align: crankshaft timing mark should align with engine block reference, and all four camshaft sprockets should align with their respective cylinder head reference marks. Install camshaft alignment pins through special tool holes in camshaft sprocket hubs to lock all four camshafts in TDC position. Take multiple photos of timing chain routing and all timing marks before proceeding. Mark chain-to-sprocket relationship with paint pen on all four camshaft sprockets and both crankshaft sprockets.
8. 8

   Remove timing chains and components
   Remove timing chain tensioners from both banks (2 tensioners per bank, 4 total). Each tensioner is secured with fasteners and must be carefully extracted. Remove timing chain guides - there are multiple fixed guides and pivoting guides in the timing system. Remove camshaft sprocket bolts while holding each camshaft with wrench on hex flat machined into camshaft. Remove camshaft sprockets. Remove timing chains from crankshaft sprockets, noting routing through guides. Remove VVT solenoids from cylinder heads. Remove crankshaft sprockets using appropriate puller if needed.
9. 9

   Remove camshafts
   Remove camshaft bearing cap bolts in reverse order of tightening sequence (loosen from ends toward center in multiple passes). Each bank has intake and exhaust camshafts with multiple bearing caps. Mark each bearing cap with bank, position, and orientation before removal. Carefully lift camshafts from cylinder heads, keeping them identified by bank and intake/exhaust position. Inspect camshaft journals and lobes for wear or scoring. Store camshafts on padded surface to prevent damage.
10. 10

    Remove rocker arms and hydraulic lash adjusters
    Remove rocker arms from each cylinder head. The DB9 V12 uses roller finger followers that pivot on hydraulic lash adjusters. Remove each rocker arm and place in numbered tray corresponding to cylinder and valve position. Remove hydraulic lash adjusters from their bores in cylinder head. Keep all lash adjusters upright and organized by position - they must be reinstalled in their original locations to maintain break-in wear patterns. Inspect rocker arm roller bearings and cam contact surfaces for wear.
11. 11

    Remove cylinder heads - left bank
    Disconnect any remaining coolant pipes, sensors, and wiring harnesses from left cylinder head. Remove cylinder head bolts in reverse of tightening sequence (loosen from ends toward center in multiple passes). Verify the exact cylinder head bolt count and locations per bank against the Aston Martin factory service manual before removal. Carefully break cylinder head loose from block using plastic mallet taps on casting bosses - never pry between sealing surfaces. Lift cylinder head straight up to prevent damage to dowel pins. Place cylinder head on padded work surface with combustion chambers facing up. Remove and discard old head gasket. Note: Verify the exact number and locations of cylinder head bolts per bank against the Aston Martin factory service manual before removal. Note: Verify the exact number of head bolts per cylinder head against the Aston Martin factory service manual before removal. Note: Head bolt count not verified - confirm exact count and locations per bank against the Aston Martin factory service manual
12. 12

    Remove cylinder heads - right bank
    Disconnect any remaining coolant pipes, sensors, and wiring harnesses from right cylinder head. Remove cylinder head bolts in reverse of tightening sequence (loosen from ends toward center in multiple passes). Verify the exact number and locations of cylinder head bolts per bank against the Aston Martin factory service manual before removal. Carefully break cylinder head loose from block using plastic mallet taps on casting bosses. The right bank has more difficult access due to steering and chassis components - take care when lifting head to avoid contact with surrounding components. Lift cylinder head straight up and place on padded work surface. Remove and discard old head gasket. Note: Verify the exact number of head bolts per cylinder head against the Aston Martin factory service manual before removal.
13. 13

    Inspect and clean sealing surfaces
    Inspect cylinder head sealing surfaces for warpage using precision straightedge and feeler gauge. Maximum allowable warpage is typically 0.05mm - check factory service manual for exact specification. Inspect engine block deck surfaces similarly. Carefully clean all gasket material from cylinder head and block deck surfaces using plastic scraper - never use metal scrapers that can gouge aluminum surfaces. Clean surfaces with brake cleaner and lint-free rags until completely free of oil, coolant, and debris. Inspect cylinder bores for glazing, scoring, or ridge wear at top of ring travel. Cover cylinder bores with clean rags to prevent debris entry. Inspect head bolt holes in block and clean with thread chaser, then blow out with compressed air.
14. 14

    Prepare cylinder heads for installation
    If cylinder heads required machining or valve service, verify all valve seals, springs, and keepers are properly installed and valve lash is within specification (if adjustable). Clean all rocker arm contact surfaces and hydraulic lash adjuster bores. Install new head gaskets on engine block, ensuring proper orientation - gaskets are bank-specific and have TOP markings. Align gasket dowel pin holes with block dowel pins. Do not apply any sealant to head gaskets unless specifically required by factory procedure. Verify all head bolt holes in block are clean, dry, and threads are in good condition.
15. 15

    Install cylinder heads
    Carefully lower right bank cylinder head onto engine block, aligning with dowel pins and head gasket. Install new cylinder head bolts finger-tight in their correct positions. Repeat process for left bank cylinder head. Following factory tightening sequence, torque all head bolts on both banks in multiple steps: Torque cylinder head bolts in multiple stepped passes followed by the specified angle torque EXACTLY per the Aston Martin factory service manual sequence and values (do not use generic values - these must be confirmed from OEM documentation). Use angle gauge to verify precise angle application. The sequence typically starts from center bolts and works outward alternating side-to-side. Note: Following the factory tightening sequence, torque all head bolts on both banks in the exact multi-pass torque plus angle procedure specified in the Aston Martin factory service manual. Do not use generic values; confirm each pass value and final angle from OEM documentation. Note: Tighten head bolts in multiple stages per the Aston Martin factory torque sequence and specification (stage torque values and final angle not verified - obtain exact figures from the factory service manual before proceeding). Note: Torque and angle specification not verified - obtain the exact multi-pass torque values and final angle stage from the Aston Martin factory service manual before tightening
16. 16

    Install rocker arms and hydraulic lash adjusters
    Install hydraulic lash adjusters into their original positions in each cylinder head, ensuring they are fully seated. Apply clean engine oil to lash adjuster bores before installation. Install rocker arms onto their respective valve stems and lash adjusters, ensuring proper orientation with roller toward camshaft lobe path. Verify each rocker arm moves freely on its pivot and contacts valve stem tip squarely.
17. 17

    Install camshafts
    Liberally coat all camshaft journals and lobes with assembly lube or clean engine oil. Carefully lower camshafts into their original positions in cylinder heads, ensuring intake and exhaust camshafts are in correct locations. Install camshaft bearing caps in their original positions and orientations - caps are numbered and have directional arrows. Install bearing cap bolts and tighten in sequence from center outward per Aston Martin factory specification in multiple passes (verify exact torque value in the service manual). Verify camshafts rotate freely by hand after installation. Note: Install bearing cap bolts and tighten in the sequence and multi-pass torque values specified in the Aston Martin factory service manual for this engine. Note: Install bearing cap bolts and tighten in the factory-specified sequence and torque in multiple passes (verify exact torque value against the Aston Martin service manual).
18. 18

    Install timing system - crankshaft components
    Install crankshaft sprockets onto crankshaft snout, ensuring keyway alignment. Install timing chain guides into engine block and tighten fasteners. Verify crankshaft is still locked at TDC position using locking tool. Begin routing timing chains per factory diagram - each bank has dedicated chain routing through primary and secondary guides.
19. 19

    Install timing system - camshaft components and timing
    Route timing chains over camshaft sprocket positions. Install camshaft sprockets onto camshafts while threading timing chains over sprocket teeth, aligning all timing marks per factory specification. Install camshaft alignment pins to lock all four camshafts in correct position. Verify paint marks on chains align with marks on sprockets. Install camshaft sprocket bolts while holding camshafts with a wrench on the hex flats, torquing to the exact value (and angle, if specified) listed in the Aston Martin factory service manual. Remove camshaft alignment pins and verify all timing marks remain aligned. Manually rotate engine two complete revolutions and recheck timing mark alignment - if marks do not realign precisely, timing is incorrect and must be corrected before proceeding. Note: Install camshaft sprocket bolts while holding camshafts with wrench on hex flats, torquing per Aston Martin factory specification (verify exact value and any TTY/angle requirement from the service manual). Note: Install camshaft sprocket bolts while holding camshafts with wrench on hex flats, torquing to the Aston Martin factory specification (verify exact value and whether a torque-plus-angle procedure applies).
20. 20

    Install timing chain tensioners
    Compress each timing chain tensioner and install retaining pin to hold in compressed position. Install new tensioner gaskets. Install tensioners into engine block and tighten mounting bolts per Aston Martin factory specification (verify exact torque value in the service manual). After all four tensioners are installed and torqued, carefully remove retaining pins to allow tensioners to apply pressure to timing chains. Manually rotate engine two more complete revolutions and verify smooth rotation and proper timing mark realignment. Note: Install tensioners into engine block and tighten mounting bolts to the Aston Martin factory-specified torque (verify exact value).
21. 21

    Install timing cover and crankshaft pulley
    Install new timing cover gasket and front crankshaft seal. Apply thin bead of RTV sealant to corners where timing cover meets cylinder head and oil pan if specified by factory procedure. Install the timing cover and tighten the bolts in the proper sequence to the torque value specified in the Aston Martin factory service manual, starting from center and working outward. Install crankshaft pulley onto crankshaft snout, aligning keyway. Install crankshaft pulley bolt and torque per Aston Martin factory specification (exact value and any torque-plus-angle sequence must be verified in the service manual) - verify if this is a TTY bolt requiring replacement. Remove crankshaft locking tool. Note: Install timing cover and tighten bolts in proper sequence per Aston Martin factory specification, starting from center and working outward (verify exact torque value in the service manual). Note: Install crankshaft pulley bolt (use a new bolt if the factory specifies it as TTY) and torque to the Aston Martin factory specification, including any required angle stage - verify exact values before final tightening. Note: Install timing cover and tighten bolts in proper sequence to the Aston Martin factory-specified torque for each bolt size, starting from center and working outward (verify exact values).
22. 22

    Install VVT solenoids and sensors
    Install VVT solenoids into cylinder heads with new O-ring seals, torquing mounting bolts to the factory-specified value. Reconnect electrical connectors to VVT solenoids. Install any camshaft or crankshaft position sensors that were removed, torquing sensor mounting bolts to the factory-specified value (verify all torque values against the Aston Martin service manual). Verify all sensor wiring is routed properly and secured with clips.
23. 23

    Install valve covers
    Install new valve cover gaskets onto valve covers, ensuring proper seating in gasket grooves. Apply small amount of RTV sealant to corners where camshaft caps meet cylinder head if specified. Position valve covers onto cylinder heads and install mounting bolts. Tighten valve cover bolts in sequence from center outward to the Aston Martin factory-specified torque (verify exact value; do not overtighten). Do not overtighten as this will distort covers and cause oil leaks. Reconnect PCV hoses and breather connections to valve covers.
24. 24

    Install exhaust manifolds
    Install new exhaust manifold gaskets onto cylinder head studs. Position exhaust manifolds onto studs and install nuts finger-tight. Torque exhaust manifold nuts in the sequence and to the value specified in the Aston Martin factory service manual, working from center outward. Install exhaust heat shields. Reconnect exhaust system at catalytic converter flanges with new gaskets and hardware. Note: Torque exhaust manifold nuts per Aston Martin factory specification in sequence from center outward (verify exact torque value in the service manual). Note: Torque exhaust manifold nuts to the Aston Martin factory-specified value in sequence from center outward (verify exact torque).
25. 25

    Install intake manifolds and fuel system
    Install new intake manifold gaskets onto cylinder heads. Position lower intake manifold sections onto cylinder heads and install mounting bolts, torquing to the factory-specified value in sequence from center outward. Install upper intake plenum with new gasket, torquing bolts to the factory-specified value (verify all torque values against the Aston Martin service manual). Reconnect all fuel injector electrical connectors per labeling. Reconnect fuel supply and return lines at fuel rail. Install throttle body with new gasket. Reconnect all vacuum lines per labeling and photos.
26. 26

    Install ignition system
    Install new spark plugs in all 12 cylinders, torquing to the exact value specified in the Aston Martin factory service manual for this engine's aluminum heads. Install ignition coils into spark plug wells and secure with mounting bolts. Reconnect all ignition coil electrical connectors per labeling. Note: Spark plug torque not verified - obtain exact specification from the Aston Martin factory service manual for this engine's aluminum heads
27. 27

    Install accessory drive components
    Install A/C compressor and mounting brackets. Install alternator and mounting hardware. Install power steering pump. Install serpentine belt per routing diagram on belt routing decal. Verify belt is properly seated on all pulleys and tensioner operates smoothly.
28. 28

    Install cooling system components
    Install thermostat with new gasket/O-ring and install thermostat housing. Reconnect heater hoses to firewall connections. Install radiator hoses. Install cooling fans and radiator assembly. Install coolant expansion tank and reconnect hoses. Verify all hose clamps are tight and properly positioned.
29. 29

    Refill fluids and perform initial checks
    Install new oil drain plug crush washer and install drain plug, torquing per Aston Martin factory specification (verify exact torque value in the service manual). Install new oil filter. Fill engine with the factory-specified quantity and grade of engine oil (verify exact capacity and oil specification in the Aston Martin service manual). Fill the cooling system with the OEM-specified coolant to the exact capacity listed in the Aston Martin factory service manual - use the vacuum fill method if available to minimize air pockets. Reconnect negative battery terminal. Turn ignition to ON position without starting engine and verify no warning lights indicating sensor disconnection. Check for fuel leaks around fuel rail connections. Note: Fill cooling system with the factory-specified quantity and type of coolant (verify exact capacity and coolant specification in the Aston Martin service manual) - use vacuum fill method if available to minimize air pockets. Note: Fill the engine with the OEM-approved oil grade and exact capacity specified in the Aston Martin factory service manual. Note: Install new oil drain plug crush washer and install drain plug, torquing to the Aston Martin factory-specified value (verify exact torque). Note: Fill engine with the Aston Martin factory-specified quantity and grade of engine oil (verify grade and capacity). Fill cooling system with the factory-specified quantity of the Aston Martin-approved coolant - use vacuum fill method if available to minimize air pockets (verify exact capacities against the service manual).
30. 30

    Initial startup and system checks
    Start engine and allow to idle. Monitor for unusual noises, vibrations, or oil pressure warning. Check for oil leaks at valve covers, timing cover, and head gasket areas. Check for coolant leaks at all connections, head gasket areas, and hose connections. Allow engine to reach operating temperature while monitoring temperature gauge. Verify cooling fans operate. Check for exhaust leaks at manifold connections. Shut down engine after reaching operating temperature and allow to cool for 30 minutes.
31. 31

    Recheck torque and fluid levels
    After engine has cooled, recheck valve cover bolt torque and timing cover bolt torque - some gaskets may compress during initial heat cycle. Check engine oil level and add if necessary to bring to full mark. Check coolant level in expansion tank and top off as needed - some air pockets may have bled out during first heat cycle. Perform thorough inspection under vehicle for any fluid leaks.

Reassembly

1. Install engine covers and acoustic panels in reverse order of removal.
2. Perform complete visual inspection of engine bay to verify all connectors, hoses, and hardware are properly installed.
3. Clear any diagnostic trouble codes that may have been set during battery disconnection.
4. Test drive vehicle under varying load conditions to verify proper operation.
5. Re-inspect for leaks after test drive and 50 miles of operation.
6. Consider performing compression test and leak-down test if head gasket failure cause is unknown to verify successful repair.

Verification

• Engine starts smoothly and idles steadily without unusual noises or vibrations.
• No oil leaks present at valve covers, cylinder head gaskets, timing cover, or any other sealing surfaces.
• No coolant leaks present at head gaskets, thermostat housing, or hose connections.
• No exhaust leaks present at manifold flanges.
• Engine reaches and maintains proper operating temperature without overheating.
• Oil pressure gauge shows normal pressure at idle and under acceleration.
• No misfires or rough running under any operating condition.
• All timing marks remain properly aligned after engine rotation.
• Compression test shows even compression across all 12 cylinders within specification.
• No diagnostic trouble codes present related to camshaft/crankshaft position correlation.

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