This procedure replaces the timing chain, guides, tensioners, and related components on the 3.5L EcoBoost V6 engine, requiring removal of the front engine covers and synchronization of camshaft and crankshaft timing.

Warnings

Tools required

Parts

• Timing chain kit (includes chains, guides, tensioners) × 1 — Use OEM Ford specification
• Timing cover gasket × 1 — Use OEM specification
• Valve cover gaskets (left and right) × 2 — Use OEM specification
• Crankshaft front seal × 1 — Use OEM specification
• Camshaft position sensor O-rings × 4 — Use OEM specification
• Oil filter × 1 — Motorcraft FL-910S or equivalent
• Oil drain plug crush washer × 1 — Use OEM specification
• Crankshaft pulley bolt (if TTY) × 1 — Verify if reusable or TTY

Fluids

• Motorcraft 0W-20 Full Synthetic — 6 qt
• Motorcraft Orange Coolant — 2 qt

Preparation

1. Ensure engine is completely cold (minimum 2 hours after last operation)
2. Disconnect negative battery terminal and wait 10 minutes for system discharge
3. Raise vehicle on lift or jack stands to access lower components
4. Remove engine splash shield and lower covers
5. Drain engine oil completely and remove oil filter
6. Drain coolant from radiator and engine block into appropriate containers
7. Remove engine air intake system and intercooler piping
8. Remove accessory drive belt
9. Install engine support fixture or attach hoist to engine lifting eyes
10. Support engine from above to allow motor mount removal
11. Remove right side motor mount to allow engine rotation for access
12. Remove both valve covers and inspect for additional issues
13. Remove all ignition coils and spark plugs to allow free engine rotation
14. Take multiple reference photos of timing mark positions before disassembly

Procedure

1. 1

   Remove Crankshaft Pulley and Harmonic Balancer
   Use breaker bar or impact wrench to remove crankshaft pulley bolt. This bolt is extremely tight and often requires impact tools. If reusing, verify it is not a torque-to-yield (TTY) design. Remove harmonic balancer using puller if necessary. Inspect balancer for wobble or separation.
2. 2

   Remove Front Timing Cover
   Remove all timing cover bolts, noting there are three different sizes (6mm, 8mm, and 10mm) in specific locations. Carefully separate timing cover from engine block using plastic pry tools. Do not damage sealing surfaces. Remove and discard timing cover gasket and front crankshaft seal. Clean all RTV and old gasket material from both mating surfaces using plastic scraper.
3. 3

   Rotate Engine to TDC Position for Cylinder 1
   Manually rotate crankshaft clockwise using socket on crankshaft bolt until cylinder 1 is at top dead center (TDC) on compression stroke. Verify timing marks on all camshaft sprockets align with marks on cylinder heads. Verify crankshaft keyway is at 12 o'clock position. Use paint pen to mark all timing positions on sprockets, chains, and engine block for verification reference. Take photos of all timing mark alignments.
   ⚠Double-check all timing marks are aligned before proceeding. Misalignment will cause engine damage.
4. 4

   Remove Primary Timing Chain Tensioners
   Locate primary timing chain tensioners on both left and right sides. Remove tensioner mounting bolts and carefully extract tensioners. Inspect tensioners for proper operation and replace if they do not compress and extend smoothly with resistance. Keep tensioners organized by cylinder bank.
5. 5

   Remove Timing Chain Guides
   Remove all timing chain guide bolts from both cylinder banks. Carefully remove upper guides, lower guides, and idler sprocket guides. Inspect guides for wear grooves deeper than 1mm - these must be replaced. The kit should include all guides regardless of wear condition.
6. 6

   Remove Primary and Secondary Timing Chains
   Remove primary timing chains from crankshaft sprocket and camshaft sprockets. Remove secondary timing chains connecting intake and exhaust camshafts on each cylinder bank. Keep all components organized by cylinder bank (left/right). Remove idler sprocket if required. Do NOT rotate crankshaft or camshafts from this point forward until reassembly is complete.
   ⚠️With chains removed, absolutely do not rotate crankshaft or camshafts. Valve-to-piston contact will occur immediately.
7. 7

   Inspect Components and Prepare New Parts
   Inspect all camshaft sprockets and crankshaft sprocket for wear, grooves, or damage. Check cam phasers for excessive play or rattling. Clean all timing component mounting surfaces thoroughly. Unpack timing chain kit and verify all components are included. Compress new tensioners using bench vise and install retaining pins or clips to hold them compressed.
8. 8

   Install New Timing Chains and Guides
   With crankshaft and camshafts still at TDC position, install new lower chain guides first. Install new primary timing chains onto crankshaft sprocket, ensuring colored links (if present) align with marks on sprockets. Route chains around idler sprocket (if equipped) and onto camshaft sprockets, verifying timing mark alignment. Install secondary chains between intake and exhaust camshafts on each bank, aligning colored links with sprocket marks. Install upper chain guides.
   Torque spec

   Chain guide bolts12 Nm (9 lb-ft)
9. 9

   Install Timing Chain Tensioners
   Install new timing chain tensioners with retaining pins still in place to keep them compressed. Install and torque tensioner mounting bolts. Carefully remove retaining pins from tensioners, allowing them to apply tension to chains. Listen for tensioners engaging properly. Verify all chains have appropriate tension and no slack.
10. 10

    Verify Timing Alignment
    Manually rotate crankshaft clockwise two complete revolutions, stopping at TDC for cylinder 1. Verify all timing marks realign exactly as they were initially. Check that colored chain links (if equipped) still align with sprocket marks. If any marks are off, timing is incorrect - remove chains and repeat installation. This verification is critical and must be perfect before proceeding.
    ⚠️If timing marks do not realign perfectly after two rotations, do not proceed. Disassemble and correct timing.
11. 11

    Install New Front Crankshaft Seal and Timing Cover
    Install new front crankshaft seal into timing cover using seal driver or appropriate socket. Ensure seal is flush and square. Install new timing cover gasket - some applications use formed gasket, others use RTV sealant per Ford specification. Position timing cover carefully onto engine block, ensuring proper alignment over crankshaft and dowel pins. Install timing cover bolts finger-tight initially.
12. 12

    Torque Timing Cover Bolts in Sequence
    Torque timing cover bolts in proper sequence starting from center and working outward. There are three bolt sizes: 6mm bolts to 10 Nm (7 lb-ft), 8mm bolts to 25 Nm (18 lb-ft), and 10mm bolts to 45 Nm (33 lb-ft). Follow factory tightening sequence diagram to ensure even gasket compression and prevent cover warping or leaks.
13. 13

    Install Crankshaft Pulley and Harmonic Balancer
    Clean crankshaft snout and install harmonic balancer, ensuring keyway aligns properly. Install crankshaft pulley bolt (use new bolt if TTY type). Torque crankshaft pulley bolt to 180 Nm (133 lb-ft). Impact wrench is typically required for proper tightening. If bolt is TTY, follow additional angle torque specification from service manual.
    Torque spec

    Crankshaft pulley bolt (stretch, replace)90 Nm (66 lb-ft)
14. 14

    Reinstall Valve Covers and Engine Components
    Install new valve cover gaskets on both cylinder banks. Position valve covers and install bolts in proper sequence, torquing to specification. Reinstall camshaft position sensors with new O-rings. Reinstall ignition coils and spark plugs. Reinstall right engine mount. Remove engine support fixture. Reinstall accessory drive belt. Reinstall air intake system and intercooler piping.
15. 15

    Complete Fluid Service and Final Checks
    Install new oil drain plug crush washer and torque drain plug. Install new oil filter and fill engine with 6 quarts of Motorcraft 0W-20 full synthetic oil. Refill cooling system with Motorcraft Orange coolant to proper level. Reinstall engine splash shields and lower covers. Reconnect battery negative terminal. Verify all tools are removed from engine bay.

Reassembly

1. Torque all fasteners to specification in proper sequence where applicable
2. Use new gaskets, seals, and crush washers for all components
3. Apply medium-strength threadlocker to cam phaser bolts per specification
4. Ensure all electrical connectors are properly seated and locked
5. Double-check accessory belt routing before starting engine
6. Verify no tools or parts remain in engine bay before closing hood

Verification

• Prime oil system by cranking engine with fuel pump fuse removed for 10-15 seconds
• Reinstall fuel pump fuse and start engine, monitoring for immediate oil pressure
• Listen for abnormal noises - engine should run smoothly without rattling or knocking
• Allow engine to reach operating temperature and verify no coolant or oil leaks
• Check for diagnostic trouble codes and clear any codes related to battery disconnection
• Verify proper engine idle quality and throttle response
• Road test vehicle under light load, listening for any timing-related noises
• Re-check all fluid levels after test drive and verify no leaks at timing cover or valve covers
• Monitor engine operation for first 100 miles, checking for any developing issues

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