This procedure replaces the timing chain tensioners on the 3.5L EcoBoost V6 engine, requiring removal of the front timing cover and timing components to access both primary and secondary tensioners.

Warnings

Tools required

Parts

• Primary timing chain tensioner × 1 — Use OEM Ford specification
• Secondary timing chain tensioners (left and right bank) × 2 — Use OEM Ford specification
• Timing cover gasket × 1 — Use OEM Ford specification
• Valve cover gaskets (left and right) × 2 — Use OEM Ford specification
• Crankshaft front seal × 1 — Use OEM Ford specification
• RTV silicone sealant (Motorcraft TA-31) × 1 — Motorcraft TA-31
• Engine oil and filter × 1 — Use OEM specification 0W-20

Fluids

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

Preparation

1. Ensure engine is completely cold
2. Disconnect negative battery cable and wait 10 minutes for airbag system discharge
3. Remove engine cover and air intake assembly
4. Drain engine oil completely and remove oil filter
5. Drain coolant from radiator and engine block drain plugs
6. Raise and secure vehicle on jack stands
7. Remove front wheels and inner fender splash shields
8. Remove accessory drive belt and belt tensioner
9. Support engine from above with engine support fixture or hoist
10. Remove right side engine motor mount to allow timing cover clearance
11. Clear workspace and organize removed fasteners by location

Procedure

1. 1

   Remove valve covers
   Disconnect ignition coils and wiring harnesses from both valve covers. Remove PCV hoses and breather tubes. Remove valve cover bolts in reverse of tightening sequence and carefully lift off both valve covers. Inspect gaskets and set aside valve covers with gaskets facing up to prevent debris contamination.
2. 2

   Remove front accessories and crankshaft pulley
   Remove power steering pump and set aside without disconnecting hydraulic lines. Remove A/C compressor mounting bolts and secure compressor aside without disconnecting refrigerant lines. Use breaker bar to hold crankshaft and remove crankshaft pulley bolt. Use harmonic balancer puller to remove crankshaft pulley from crankshaft snout without damaging woodruff key.
   ⚠Do not use impact tools on crankshaft pulley bolt as this can damage crankshaft position sensor tone wheel.
3. 3

   Remove timing cover
   Disconnect crankshaft position sensor and camshaft position sensors. Remove all timing cover bolts noting the different lengths and locations (8mm and 10mm bolts in specific positions). Carefully separate timing cover from engine block using plastic pry bars only at designated pry points. Remove timing cover and old gasket material. Do not damage sealing surfaces.
4. 4

   Rotate engine to TDC and verify timing marks
   Rotate crankshaft clockwise using crankshaft bolt until cylinder #1 is at TDC firing position. Verify all timing marks align: crankshaft keyway at 12 o'clock, left camshaft timing marks aligned, right camshaft timing marks aligned. Mark chain-to-sprocket positions with paint pen for reference. Take photos for reassembly reference.
   ℹ️All six timing marks must be perfectly aligned before proceeding. Left bank exhaust cam, left bank intake cam, right bank exhaust cam, right bank intake cam, crankshaft, and balance shaft.
5. 5

   Install camshaft and crankshaft holding tools
   Install camshaft positioning tools into the rear of both cylinder heads through the access holes in the rear of the heads. Install crankshaft positioning tool into the crankshaft keyway. These tools prevent rotation during tensioner replacement. Verify tools are fully seated and secure before proceeding.
   ⚠️Holding tools MUST be installed before loosening any timing chain components. Failure to use these tools will result in lost timing and engine damage.
6. 6

   Remove primary timing chain tensioner
   Locate the primary timing chain tensioner on the front lower left side of the engine block. Remove the tensioner mounting bolts and carefully extract the tensioner. Note the orientation and position of the tensioner arm and blade. Inspect the chain guides for wear or damage while tensioner is removed.
   ⚠Do not allow timing chain to become slack or fall off sprockets during tensioner removal.
7. 7

   Remove secondary timing chain tensioners
   Access the left bank secondary tensioner from the left side of the engine and right bank tensioner from the right side. Remove tensioner bolts from both secondary tensioners. Carefully remove both secondary tensioners noting their orientation. Keep left and right bank components separated.
8. 8

   Inspect timing chain components
   With tensioners removed, inspect all timing chains for wear, stretching, or damaged links. Inspect chain guides and pivot arms for wear grooves or cracks. Check all sprockets for worn teeth. Inspect VCT actuators for free play or leakage. Replace any worn components as necessary before proceeding.
   ℹ️If timing chains show wear or stretch beyond specification, replace chains, guides, and tensioners as a complete set.
9. 9

   Prepare and install new primary tensioner
   Remove new primary tensioner from packaging. Manually compress the tensioner piston fully and insert retaining pin or wire clip through the hole to keep it compressed. Apply clean engine oil to tensioner bore in engine block. Install compressed tensioner with retaining pin still in place and torque mounting bolts to specification in a crossing pattern.
   ⚠Do NOT remove retaining pin yet. Pin must remain installed until all timing components are assembled and verified.
10. 10

    Prepare and install new secondary tensioners
    Compress both new secondary tensioners and install retaining pins to hold them compressed. Apply clean engine oil to tensioner bores. Install left bank secondary tensioner and torque bolts to specification. Install right bank secondary tensioner and torque bolts to specification. Verify tensioner mounting is secure but leave retaining pins installed.
11. 11

    Verify timing alignment and release tensioners
    Double-check all timing marks are still perfectly aligned with holding tools in place. Verify all chains are properly seated on sprockets. Remove retaining pins from all three tensioners allowing them to apply tension to their respective chains. Verify chains have proper tension and are tracking correctly on all sprockets.
    ⚠️Verify timing marks one final time before removing holding tools. Incorrect timing will cause immediate engine damage on startup.
12. 12

    Remove holding tools and verify free rotation
    Carefully remove camshaft positioning tools from both cylinder heads. Remove crankshaft positioning tool from crankshaft. Manually rotate crankshaft slowly clockwise two complete revolutions using crankshaft bolt. Verify engine rotates freely without binding. Stop at TDC cylinder #1 and verify all timing marks align perfectly again.
    ⚠If engine binds or timing marks do not realign after two rotations, STOP immediately. Disassemble and verify timing chain installation.
13. 13

    Install new timing cover seal and prepare cover
    Remove old crankshaft seal from timing cover using seal puller. Clean timing cover thoroughly and inspect for cracks or damage. Install new crankshaft front seal into timing cover using seal driver, ensuring it is flush and square. Clean all gasket surfaces on timing cover and engine block with razor blade and solvent. Apply RTV silicone to designated areas per Ford service specifications.
14. 14

    Install timing cover
    Position new timing cover gasket on engine block alignment pins. Carefully install timing cover ensuring crankshaft seal slides over crankshaft snout without damage. Start all timing cover bolts by hand, noting correct bolt lengths and positions. Tighten 8mm timing cover bolts in specified sequence to 25 Nm, then tighten remaining bolts to 16 Nm. Reconnect crankshaft and camshaft position sensors and torque to specification.
15. 15

    Reinstall crankshaft pulley and accessories
    Clean crankshaft snout and pulley bore. Install crankshaft pulley ensuring woodruff key is properly aligned. Install new crankshaft pulley bolt and torque to 203 Nm (150 lb-ft) while holding crankshaft from rotation. Reinstall A/C compressor and power steering pump with mounting bolts torqued to specification. Install accessory drive belt tensioner and belt.

Reassembly

1. Install new valve cover gaskets on both cylinder heads
2. Install valve covers and torque bolts in proper sequence to 10 Nm (7 lb-ft)
3. Reconnect all ignition coils, PCV hoses, and breather tubes
4. Reinstall right side engine motor mount and torque to specification
5. Remove engine support fixture
6. Reinstall inner fender splash shields and front wheels
7. Install new oil filter and refill engine with 6 quarts of Motorcraft 0W-20 oil
8. Refill cooling system with Motorcraft Orange Coolant to proper level
9. Reconnect negative battery cable
10. Reinstall air intake assembly and engine cover

Verification

• Start engine and verify it runs smoothly without unusual noises, particularly rattling from timing chain area
• Check for oil leaks around timing cover, valve covers, and crankshaft seal while engine is running
• Allow engine to reach operating temperature and verify no coolant leaks from timing cover area
• Verify check engine light does not illuminate and scan for diagnostic trouble codes
• Listen for proper tensioner operation - no slapping or rattling sounds from timing chains
• Road test vehicle under various loads and RPM ranges to verify proper engine performance
• Recheck oil level after initial run and top off if necessary
• Inspect timing cover area for any seepage after 100 miles of operation

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