Complete timing chain, tensioner, and guide replacement on the 3.5L EcoBoost engine, including timing cover removal, cam phaser service, and timing alignment.

Warnings

Tools required

Parts

• Timing chain kit (includes chains, guides, tensioners) × 1 — Motorcraft 3.5L EcoBoost timing kit or equivalent
• Timing cover gasket × 1 — Use OEM specification
• Left valve cover gasket × 1 — Use OEM specification
• Right valve cover gasket × 1 — Use OEM specification
• Oil drain plug crush washer × 1 — Use OEM specification
• Engine oil filter × 1 — Motorcraft FL-910-S or equivalent
• RTV silicone gasket maker × 1 — Motorcraft TA-31 or equivalent
• Threadlocker medium strength × 1 — Loctite 243 or equivalent

Fluids

• Motorcraft 5W-20 Synthetic Blend engine oil — 6 qt
• Motorcraft Orange Coolant (partial refill) — 3 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Disconnect negative battery cable and wait 10 minutes for airbag system to discharge
3. Remove engine cover (pull upward to release clips)
4. Raise and support vehicle on jack stands at all four corners
5. Remove front wheels for access to lower engine components
6. Drain engine oil completely and remove oil filter
7. Drain cooling system from radiator petcock and lower radiator hose
8. Remove front bumper cover for access to cooling components
9. Remove grille and active grille shutters if equipped
10. Remove radiator, intercooler, and A/C condenser as assembly
11. Remove serpentine drive belt
12. Support engine with support bar or hoist from above
13. Remove upper engine mount bracket
14. Label and disconnect ignition coils from both cylinder heads
15. Remove all spark plugs to reduce compression during rotation

Procedure

1. 1

   Remove valve covers and accessories
   Remove left and right valve covers by removing bolts in reverse of tightening sequence. Remove PCV hoses and breather tubes. Disconnect variable camshaft timing (VCT) solenoid electrical connectors on both banks. Remove accessory brackets attached to timing cover including power steering pump (support aside without disconnecting hoses), A/C compressor (support aside), and alternator.
2. 2

   Remove crankshaft pulley
   Remove crankshaft pulley center bolt. This bolt is torqued to 133 lb-ft and typically requires an impact wrench. Hold crankshaft from rotating using a holding tool engaged in flywheel ring gear or a strap wrench on the pulley. Once bolt is removed, use a three-jaw puller to remove the crankshaft pulley from the snout. Do not pry against timing cover.
   ⚠Never use a wedge or pry bar between pulley and timing cover as this will damage the cover sealing surface.
   Torque spec

   Crankshaft pulley bolt (stretch, replace)90 Nm (66 lb-ft)
3. 3

   Remove timing cover
   Remove all timing cover bolts noting their different lengths and locations. There are three different bolt sizes: 6mm, 8mm, and 10mm. Remove oil pan-to-timing cover bolts from below. Carefully pry timing cover away from engine block using plastic pry points only. Remove and discard timing cover gasket. Clean all gasket surfaces thoroughly with plastic scraper, ensuring no RTV or gasket material remains.
4. 4

   Verify and document timing alignment
   Rotate crankshaft clockwise (viewed from front) until cylinder 1 is at TDC on compression stroke. Verify timing marks: crankshaft keyway should point upward, left bank camshaft timing marks should align with cylinder head surface, right bank camshaft timing marks should align with cylinder head surface. Take clear photos of all timing mark positions. Mark chain-to-sprocket relationship with paint pen if chains are not being replaced.
   ⚠️This is the most critical step. Incorrect timing mark documentation will result in catastrophic engine damage during startup.
5. 5

   Remove primary timing chains
   Collapse left and right timing chain tensioners by removing tensioner bolts. Note the tensioner orientation. Remove tensioner arms. Remove timing chain guides by removing guide bolts. Remove left and right primary timing chains from camshaft phasers and crankshaft sprocket. Do not rotate crankshaft or camshafts from this point forward until reassembly is complete.
   ⚠️Do not rotate crankshaft or camshafts independently after chain removal. Lock camshafts in position if necessary.
   Torque spec

   Chain guide bolts12 Nm (9 lb-ft)
6. 6

   Remove cam phasers and secondary chains (if equipped)
   Hold each camshaft stationary using a wrench on the camshaft hex. Remove cam phaser bolts from intake and exhaust camshafts on both banks. Remove cam phasers. If vehicle has secondary timing chains (connecting intake and exhaust cams), remove secondary chain tensioners and guides, then remove secondary chains. Keep all components organized by bank (left/right) and position (intake/exhaust).
7. 7

   Inspect and replace components
   Inspect all timing chain guides for excessive wear, cracks, or broken tabs. Inspect tensioner arms for wear on chain contact surface. Inspect cam phaser teeth and chain sprocket teeth for wear. Replace all chains, guides, tensioners, and arms with new components from timing chain kit. Inspect crankshaft sprocket for wear and replace if necessary. Inspect camshaft sprockets and replace if worn.
   ℹ️Even if some components appear serviceable, replace all items included in the timing chain kit to ensure longevity and prevent premature failure.
8. 8

   Install cam phasers and secondary chains
   If equipped with secondary chains, install new secondary chains on intake and exhaust camshafts with timing marks aligned per factory specification. Install secondary chain guides and tensioners (compress tensioners and pin before installation). Install cam phasers onto camshafts ensuring proper alignment of dowel pins. Apply medium-strength threadlocker to cam phaser bolts. Hold camshafts with wrench on hex and torque cam phaser bolts to specification. Verify timing marks remain aligned.
   Torque spec

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

   Install primary timing chain guides
   Install new left and right primary timing chain guides to engine block and cylinder heads. Torque guide bolts to specification. Ensure guides are properly seated and not bent or damaged. Install idler sprocket if removed, torquing to specification.
   Torque spec

   Chain guide bolts12 Nm (9 lb-ft)
10. 10

    Install primary timing chains
    Verify crankshaft is at TDC with keyway pointing up and all camshaft timing marks are aligned. Install left primary timing chain over crankshaft sprocket and left bank cam phasers, ensuring colored links (if present) align with timing marks. Install right primary timing chain similarly. Do not force chains; if they don't fit easily, timing marks are not correctly aligned. Install tensioner arms onto pivot points.
    ⚠️Triple-check all timing mark alignment before proceeding. One tooth off will cause engine damage.
11. 11

    Install timing chain tensioners
    Compress new timing chain tensioners fully and install retaining pins or clips to hold them compressed. Install compressed tensioners into engine and torque tensioner bolts to specification. Carefully remove retaining pins/clips to apply tension to chains. Verify chains are tight and properly seated on all sprockets. Rotate crankshaft two complete revolutions clockwise and verify all timing marks realign correctly at TDC.
    ⚠Remove tensioner pins slowly and carefully. Ensure your hands are clear of the chain path.
    Torque spec

    Primary chain tensioner bolts25 Nm (18 lb-ft)
12. 12

    Install timing cover
    Clean timing cover and apply new gasket or RTV silicone per manufacturer specifications (typically a bead on cover mating surface). Install timing cover carefully, ensuring it seats evenly and does not pinch gasket. Install all timing cover bolts finger-tight first, then torque in proper sequence: 6mm bolts to 7 lb-ft, 8mm bolts to 18 lb-ft, and 10mm bolts to 33 lb-ft. Allow RTV to cure per manufacturer instructions if used (typically 30 minutes before oil fill).
    ℹ️Do not over-torque 6mm bolts as they can strip easily. Use a calibrated torque wrench.
13. 13

    Install crankshaft pulley and accessories
    Clean crankshaft snout and pulley bore. Install crankshaft pulley onto snout, ensuring keyway aligns. Install new crankshaft pulley bolt and torque to 133 lb-ft. Reinstall alternator, A/C compressor, power steering pump, and all brackets. Install serpentine belt.
    Torque spec

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

    Install valve covers and complete reassembly
    Install new valve cover gaskets. Apply small dab of RTV at camshaft cap corners if specified. Install valve covers and torque bolts in proper sequence to specification. Reconnect VCT solenoid connectors, PCV hoses, and breather tubes. Install spark plugs. Reinstall ignition coils. Reinstall engine mount bracket. Remove engine support. Reinstall cooling system components (radiator, intercooler, A/C condenser). Reinstall grille, active grille shutters, and bumper cover.
15. 15

    Fill fluids and final checks
    Install new oil drain plug crush washer and torque drain plug to specification. Install new oil filter. Fill engine with 6 quarts of Motorcraft 5W-20 synthetic blend oil. Refill cooling system with Motorcraft Orange coolant. Reinstall front wheels and lower vehicle. Reconnect battery. Before starting, manually rotate crankshaft one full revolution by hand using a socket on the crankshaft bolt to verify no binding or interference. Prime oil system if possible.

Reassembly

1. Timing alignment must be verified before cranking the engine
2. All fasteners must be torqued to specification in proper sequence
3. Allow RTV silicone to cure fully before filling fluids if used on timing cover
4. Verify all electrical connectors are properly seated and locked
5. Check for any forgotten bolts or loose components before startup

Verification

• Start engine and verify it runs smoothly without unusual noises, misfires, or timing-related codes
• Check for oil leaks around timing cover, valve covers, and oil drain plug
• Check for coolant leaks at all disturbed connections
• Verify no check engine light or diagnostic trouble codes are present
• Allow engine to reach operating temperature and verify proper cooling system operation
• Listen for timing chain rattle during cold start (should be minimal or absent)
• Test drive vehicle and verify normal power delivery and no hesitation or rough running
• Recheck oil level after test drive and top off if necessary
• Perform final visual inspection of all work areas for leaks or loose components after 100 miles of driving

More procedures for this vehicle