Timing Chain Guide

Replace worn or damaged timing chain guides on the 6.0L V12 engine, requiring extensive disassembly of engine accessories, timing covers, and timing system components.

Warnings

Tools required

Parts

• Timing chain guide set (upper and lower guides) × 1 — Use OEM specification
• Timing cover gasket set × 1 — Use OEM specification
• Valve cover gaskets (left and right) × 2 — Use OEM specification
• Crankshaft front seal × 1 — Use OEM specification
• Timing chain tensioner seals × 2 — Use OEM specification
• Engine oil × 11 — 5W-30 meeting Aston Martin specification
• Coolant (OAT type) × 11 — 50/50 premix
• Timing chain guide bolts × 1 — Replace if worn per OEM
• Serpentine belt × 1 — Use OEM specification

Fluids

• engine_oil — 10.5 qt
• coolant — 10.5 qt

Preparation

1. Ensure vehicle is on a level surface with parking brake applied and wheels chocked
2. Disconnect negative battery cable and wait 10 minutes for system discharge
3. Remove engine cover(s) by releasing snap fasteners
4. Photograph all vacuum lines, electrical connectors, and hose routing for reassembly reference
5. Drain engine oil completely and drain cooling system into appropriate containers
6. Allow engine to cool completely if recently operated (minimum 2 hours)

Procedure

1. 1

   Remove Upper Engine Components
   Remove the intake plenum assembly by disconnecting throttle body connectors, MAP sensor, and vacuum lines. Remove the intake manifold fasteners (verify exact count and Torx/E-Torx sizes per OEM manual) and lift the intake assembly clear. Disconnect fuel lines using proper quick-disconnect tools and cap all openings. Remove ignition coil packs from all 12 cylinders by removing their mounting fasteners and electrical connectors (verify fastener type against the vehicle before ordering tools). Store in order to maintain cylinder position.
2. 2

   Remove Valve Covers
   Disconnect all remaining electrical connectors and breather hoses from both valve covers. Remove valve cover bolts in reverse of tightening sequence (work from outside toward center). Carefully lift valve covers away, noting any dowel pin locations. Inspect valve cover gaskets and replace if any deterioration is visible.
   Torque spec

   Valve Cover Bolts10 Nm (7 lb-ft)
3. 3

   Remove Accessory Drive System
   Release tensioner and remove serpentine belt. Remove alternator by disconnecting electrical connections and removing mounting bolts. Remove power steering pump (do not disconnect lines; secure pump aside). Remove A/C compressor mounting bolts and secure compressor aside without disconnecting refrigerant lines. Remove idler pulleys and tensioner assembly from front of engine.
4. 4

   Remove Front Engine Mounts and Support Engine
   Install engine support fixture across engine bay or attach hoist to engine lifting eyes. Remove front engine mount fasteners. Carefully raise engine approximately 25-50mm to provide clearance for timing cover removal. Ensure all hoses and wiring have adequate slack for this movement.
5. 5

   Remove Crankshaft Pulley
   Lock crankshaft using appropriate locking tool inserted into timing position. Use breaker bar and appropriate socket to remove crankshaft pulley center bolt; this bolt is installed at very high torque and may require significant force to break loose. Verify exact crankshaft pulley bolt specification against Aston Martin service data before removal. Remove harmonic balancer/pulley using appropriate puller if needed; do not pry against timing cover. Discard the crankshaft pulley bolt if it is a torque-to-yield (single-use) fastener per Aston Martin specification. Discard the crankshaft pulley bolt if it is a torque-to-yield (single-use) fastener per Aston Martin specification. Inspect crankshaft nose for damage. Note: Use breaker bar and appropriate socket to remove crankshaft pulley center bolt (verify breakaway torque per OEM manual; this bolt is torque-to-yield and typically requires very high removal force). The crankshaft pulley bolt must be replaced on reassembly. Note: Use breaker bar and appropriate socket to remove crankshaft pulley center bolt (removal torque exceeds the install specification; verify the exact crankshaft bolt torque-plus-angle procedure against Aston Martin workshop documentation before reassembly).
   Torque spec

   Crankshaft Pulley Bolt238 Nm (176 lb-ft)
6. 6

   Drain and Remove Coolant Components
   Disconnect upper and lower radiator hoses from timing cover. Remove water pump by removing its mounting fasteners if required for timing cover clearance. Verify water pump mounting location and whether removal is necessary per OEM procedure. Disconnect coolant bypass hoses and heater hoses as necessary for timing cover clearance. Disconnect coolant bypass hoses and heater hoses as necessary for timing cover clearance. Note: Remove water pump by removing its mounting fasteners. Confirm water pump mounting location and whether it must be removed for timing cover access against Aston Martin service documentation before proceeding. Note: Verify water pump location and its relationship to the timing cover against Aston Martin workshop documentation, then remove the water pump as required for timing cover clearance.
7. 7

   Remove Timing Cover
   Remove all timing cover bolts, noting different lengths and locations. There may be multiple bolt sizes around the perimeter (verify exact bolt count, locations, and sizes per OEM manual). Remove bolts in a crisscross pattern to avoid warping the cover. Carefully separate timing cover from engine block using plastic pry points only (do not damage sealing surfaces). Remove and discard timing cover gasket.
   Torque spec

   Timing Cover Bolt22 Nm (16 lb-ft)
8. 8

   Verify TDC Position and Lock Crankshaft
   Rotate crankshaft to Top Dead Center (TDC) position for cylinder 1. Verify timing marks on crankshaft sprocket align with marks on engine block. Install camshaft locking tools into both cylinder banks to lock all four camshafts (two per bank) in position. Confirm the correct timing/locking sequence relative to timing cover removal against Aston Martin service procedure. Verify all alignment marks are correctly positioned before proceeding. This is critical for proper reassembly timing. Note: Install camshaft locking tools into both cylinder banks to lock the camshafts in position (verify camshaft count and locking tool engagement points per OEM manual).
   ⚠️Do not proceed unless all timing marks are properly aligned and camshaft locking tools are fully engaged. Incorrect positioning will result in valve-to-piston contact upon startup.
9. 9

   Release Timing Chain Tensioners
   Release hydraulic pressure from timing chain tensioners on both banks. Remove tensioner mounting bolts and carefully extract tensioners. Inspect tensioner operation and seals; replace tensioner seals during reassembly. With tensioners removed, timing chains will have slack.
   Torque spec

   Tensioner Bolt27 Nm (20 lb-ft)
10. 10

    Remove Timing Chain Guides
    Locate all timing chain guide mounting bolts. Each bank has multiple guides (upper guide, lower guide, and possibly intermediate guides). Remove guide bolts securing the worn guides. Carefully extract guides through available access points. Inspect guides for wear patterns, scoring, or material loss. Inspect timing chain for wear, elongation, or damaged links while accessible.
    Torque spec

    Guide Bolts10 Nm (7 lb-ft)
11. 11

    Inspect Timing Chain and Sprockets
    With guides removed, thoroughly inspect timing chains for elongation, wear, or damaged rollers. Check all sprockets (crankshaft and camshaft) for wear, hooking, or damage. Measure timing chain stretch if possible using a straightedge across multiple links. If chain or sprockets show significant wear, replacement is recommended while system is disassembled. Clean all timing chain contact surfaces.
12. 12

    Install New Timing Chain Guides
    Position new timing chain guides into their mounting locations. Ensure guides are properly seated against their stops and alignment features. Install new guide bolts (if specified as replacement items) and tighten to specification. Follow manufacturer installation sequence if specified. Verify guides do not interfere with chain movement.
    Torque spec

    Guide Bolts10 Nm (7 lb-ft)
13. 13

    Install Timing Chain Tensioners
    Install new tensioner seals if provided. Compress tensioners to their installation position using appropriate tool or bench vise. Lock tensioners in compressed position using retaining pins or clips. Install tensioners with new seals and tighten mounting bolts to specification. Do not release tensioner locks yet.
    Torque spec

    Tensioner Bolt27 Nm (20 lb-ft)
14. 14

    Verify Timing Alignment and Release Tensioners
    With camshaft locking tools still installed, verify crankshaft is still at TDC and all timing marks align correctly. Verify timing chains are properly engaged on all sprockets. Release timing chain tensioner locking pins/clips to apply tension to chains. Remove camshaft locking tools. Manually rotate crankshaft two complete revolutions clockwise (viewed from front). Reinstall camshaft locking tools and verify timing marks realign perfectly.
    ⚠️If timing marks do not realign after two crankshaft rotations, stop immediately. Disassemble and verify correct installation before proceeding.
15. 15

    Install Timing Cover with New Gasket
    Clean all gasket surfaces on engine block and timing cover using plastic scraper. Ensure surfaces are free of oil, coolant, and old gasket material. Install new timing cover gasket, using minimal RTV sealant only at specified locations (typically block-to-oil pan joints). Install new crankshaft front seal into timing cover if not already installed. Position timing cover carefully over crankshaft nose and align with dowel pins. Install timing cover bolts hand-tight first, then tighten 8mm bolts in specified sequence to specification.
    Torque spec

    Timing Cover Bolt22 Nm (16 lb-ft)
16. 16

    Install Crankshaft Pulley and Accessory Components
    Clean crankshaft nose and pulley mating surfaces. Install harmonic balancer/crankshaft pulley onto crankshaft nose. Install new crankshaft pulley bolt and tighten to specification using crankshaft locking tool. Reinstall water pump with new gasket, tightening fasteners evenly. Reconnect all coolant hoses to timing cover and water pump.
    Torque spec

    Crankshaft Pulley Bolt238 Nm (176 lb-ft)
17. 17

    Reinstall Accessory Drive Components
    Reinstall A/C compressor to mounting brackets and tighten fasteners. Reinstall power steering pump and tighten mounting bolts. Reinstall alternator with electrical connections. Install new serpentine belt following routing diagram (typically found on radiator support or under hood). Install belt tensioner and idler pulleys.
18. 18

    Lower Engine and Reinstall Mounts
    Carefully lower engine back to original position using support fixture or hoist. Reinstall front engine mount fasteners and tighten to specification. Remove engine support equipment. Verify engine sits properly in mounts without stress on any component.
19. 19

    Reinstall Valve Covers
    Install new valve cover gaskets onto valve covers, ensuring proper seating in gasket channels. Position valve covers onto cylinder heads, aligning with dowel pins if equipped. Install valve cover bolts and tighten in proper sequence (center outward) to the Aston Martin specified torque (typically a low value for cam-cover fasteners; verify exact spec before tightening). Do not overtighten. Reconnect breather hoses and electrical connectors to valve covers.
    Torque spec

    Valve Cover Bolts10 Nm (7 lb-ft)
20. 20

    Reinstall Upper Engine Components
    Reinstall ignition coil packs to all 12 cylinders in their original positions with electrical connectors. Reconnect fuel lines using proper installation technique to ensure clips are fully engaged. Position intake manifold with new gaskets if required, and tighten mounting fasteners evenly. Reinstall intake plenum assembly and reconnect all vacuum lines, sensors, and throttle body connectors according to reference photos.
21. 21

    Refill Fluids and Reconnect Battery
    Install new engine oil drain plug with new washer if required. Refill engine with the OEM-specified quantity of engine oil meeting Aston Martin specification (verify capacity and viscosity grade per owner's manual/service data). Close cooling system and refill with the coolant type and 50/50 mixture specified by Aston Martin; verify exact coolant capacity against factory specification before filling. Bleed cooling system according to manufacturer procedure. Reconnect negative battery cable. Reinstall engine covers. Note: Refill engine with engine oil of the viscosity and specification required by Aston Martin for this engine; verify exact oil capacity against factory specification before filling. Note: Close cooling system and refill with the OEM-specified coolant (correct Aston Martin specification, 50/50 premix) to the specified capacity; verify capacity per service data. Note: Refill engine with the Aston Martin specified oil capacity and grade (verify exact capacity and viscosity against factory documentation for this dry-sump V12). Note: Close cooling system and refill with the Aston Martin specified coolant type and capacity as a 50/50 premix (verify exact capacity and coolant chemistry against factory documentation).
22. 22

    Initial Start and System Check
    Perform final visual inspection of all connections, fasteners, and hose routing. Start engine and immediately verify oil pressure indication. Listen for abnormal noises, particularly from timing chain area. Allow engine to reach operating temperature while monitoring for leaks at timing cover, valve covers, and coolant connections. Verify smooth idle and proper engine operation throughout RPM range.

Reassembly

1. Reassembly follows removal in reverse order with new gaskets and seals installed at all locations
2. Ensure all timing alignment marks are verified multiple times before final assembly
3. Tighten all fasteners to specified torque values using proper sequence where applicable
4. Route all wiring harnesses and hoses according to reference photos to avoid interference or chafing
5. Bleed cooling system completely to remove air pockets from V12 engine

Verification

• Start engine and verify immediate oil pressure indication on instrument cluster
• Listen for timing chain noise or abnormal valve train sounds; timing system should be quiet
• Verify no leaks from timing cover, valve covers, or coolant connections after reaching operating temperature
• Test drive vehicle and verify smooth acceleration without hesitation, misfires, or timing-related issues
• Scan for diagnostic trouble codes using appropriate scan tool; verify no timing-related faults
• Recheck engine oil level after initial operation and top off if necessary
• Monitor oil level and timing cover area for leaks during first 500 miles of operation

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