Engine Mount - Strut

This procedure covers removal and replacement of the engine mount strut (torque rod/damper) on a 2009 Aston Martin DB9 6.0L V12, requiring engine support and undercarriage access.

Warnings

Tools required

Parts

• Engine mount strut (torque rod assembly) × 1 — Use OEM specification
• Mount strut hardware kit (if not included with mount) × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Ensure engine and exhaust components are completely cool to the touch
3. Disconnect negative battery cable and secure away from terminal
4. Raise vehicle on lift or support securely on jack stands rated for vehicle weight at proper lift points
5. Remove engine undertray panels by removing Torx fasteners around perimeter (retain fasteners for reinstallation)
6. Apply penetrating oil to engine mount strut fasteners and allow to soak for 15-30 minutes if corrosion is visible
7. Inspect existing mount strut for failure mode (cracking, separation, leaking hydraulic fluid) to confirm diagnosis

Procedure

1. 1

   Position engine support equipment
   Install engine support fixture across engine bay, or position adjustable transmission jack with wooden block under oil pan (NOT directly against pan). Support engine weight but do not lift yet. Ensure support is centered and stable with no risk of slipping. Engine support fixture is preferred method to avoid risk of oil pan damage.
2. 2

   Document engine position
   Before loosening any fasteners, mark the installed position of the engine mount strut relative to both the engine bracket and chassis/subframe bracket using paint pen or marker. These alignment marks will aid reinstallation and prevent excessive engine misalignment. Photograph mount orientation from multiple angles.
3. 3

   Relieve tension on mount strut
   Slowly raise engine support fixture or jack approximately 3-5mm (1/8 inch) to transfer engine weight from mount strut to support equipment. Monitor engine movement carefully. The goal is to unload the strut slightly, not lift engine significantly. Excessive lifting can stress other mounts, hoses, and wiring.
4. 4

   Remove upper mount strut fasteners
   Locate the upper mounting point where strut attaches to engine block or engine bracket. Remove the upper mounting hardware. This typically consists of a through-bolt with nut, or two mounting bolts securing the strut bracket to the engine. Fastener size and configuration must be verified against OEM documentation for this platform. Remove completely and retain hardware if reusing (inspect for thread damage or elongation). Note: Fastener head size and configuration must be verified against OEM documentation before beginning. Note: Fastener size and head type must be verified against OEM documentation for this platform; do not assume a specific size. Note: Fastener configuration and size to be verified against OEM documentation for this platform
5. 5

   Remove lower mount strut fasteners
   From underneath vehicle, locate the lower mounting point where strut attaches to subframe or chassis bracket. Remove the lower mounting hardware. This typically consists of a through-bolt with nut or two mounting bolts. Fastener size and configuration must be verified against OEM documentation for this platform. Support strut by hand as final fastener is removed to prevent dropping. Note: Fastener head size and configuration must be verified against OEM documentation before beginning. Note: Fastener size and head type must be verified against OEM documentation for this platform; do not assume a specific size. Note: Fastener configuration and size to be verified against OEM documentation for this platform
6. 6

   Remove engine mount strut
   With both upper and lower fasteners removed, carefully extract the engine mount strut assembly from between the engine and chassis/subframe. May require maneuvering around adjacent components or slight repositioning of engine support. Inspect removed strut for failure evidence (cracks in rubber, separation of bonded joints, hydraulic fluid leakage if fluid-filled type). Inspect mounting brackets on engine and chassis for damage, cracks, or excessive wear.
7. 7

   Clean mounting surfaces
   Use wire brush to clean mounting surfaces on both engine bracket and chassis/subframe bracket. Remove corrosion, old thread-locking compound residue, and debris. Inspect mounting bolt holes for thread damage or elongation. Inspect brackets for cracks or deformation that would compromise new mount installation.
8. 8

   Position new engine mount strut
   Position new engine mount strut between engine bracket and chassis/subframe bracket, aligning with the reference marks made during removal. Orientation is critical—ensure strut is not installed backwards or inverted. Compare orientation carefully to old part and reference photos. Strut may have directional arrow or 'top' marking.
9. 9

   Install lower mount strut fasteners loosely
   Insert lower mounting hardware (bolt or through-bolt with nut) and thread by hand until just snug. Do not torque yet. Hardware should pass through strut bushing and bracket cleanly without forcing. If new hardware is provided with replacement strut, use new hardware and discard old.
10. 10

    Install upper mount strut fasteners loosely
    Insert upper mounting hardware (bolt or through-bolt with nut) and thread by hand until just snug. Do not torque yet. May require slight adjustment of engine support to align holes. Use pry bar if needed to shift engine position slightly for alignment, but avoid forcing fasteners.
11. 11

    Lower engine to operating position
    Slowly and carefully lower engine support fixture or jack to transfer engine weight back onto the new mount strut. Engine should settle into natural position with strut bearing load. Monitor for binding or misalignment. Once engine weight is fully on mounts, remove support equipment or retract to clear position.
12. 12

    Torque mount strut fasteners
    With engine weight on mount strut in operating position, torque all mount fasteners to specification. Torque fasteners in the sequence specified by OEM documentation for this platform; if unspecified, snug both then final-torque with engine at rest in operating position. Apply medium-strength thread-locking compound to threads before final torque if specified by manufacturer. Fastener torque specification must be obtained from OEM documentation for this application before final torque; do not rely on a generic range. Torque with engine at rest in normal position, not supported. Note: Fastener torque specification must be verified against OEM documentation for this platform before final torque; do not rely on a generic estimate. Note: Fastener torque specification must be verified against OEM documentation before final torque; do not rely on an assumed value as mount bolt sizes vary significantly. Note: Torque value to be obtained from OEM documentation for this platform before final torque
13. 13

    Verify engine alignment
    Visually inspect engine position and alignment. Check clearances around engine bay to ensure engine sits in proper position. Look for interference between engine components and chassis/body. Check that other engine mounts are not under excessive stress or misaligned. Rock engine gently by hand to confirm mount is properly seated and functional.
14. 14

    Reinstall undertray panels
    Reinstall engine undertray panels using original Torx fasteners. Ensure all fasteners are properly seated and panels fit flush without gaps or misalignment. Do not overtighten plastic fasteners.

Reassembly

1. Reconnect negative battery cable and verify electrical systems function normally
2. Start engine and observe for abnormal vibration, noise, or movement at idle and under light throttle application
3. Lower vehicle from lift or jack stands
4. Test drive vehicle to verify normal operation and absence of excessive vibration or noise during acceleration and deceleration

Verification

• Engine mount strut is securely fastened at both upper and lower mounting points with all hardware torqued to specification
• Engine sits level in engine bay with proper clearances to surrounding components
• No abnormal vibration is felt at idle or during acceleration/deceleration
• No clunking or knocking sounds occur during throttle application or when shifting transmission into gear
• All undertray panels are reinstalled and secure

Related trouble codes on this vehicle

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