This procedure replaces the timing chain guides on the 3.5L EcoBoost V6 engine, requiring removal of the front timing cover and precise alignment of timing marks.

Warnings

Tools required

Parts

• Timing chain guide (left) × 1 — Use OEM Ford specification
• Timing chain guide (right) × 1 — Use OEM Ford specification
• Timing cover gasket × 1 — Use OEM Ford specification
• Valve cover gaskets × 2 — Use OEM Ford specification
• Crankshaft front seal × 1 — Use OEM Ford specification
• Engine oil and filter × 1 — Motorcraft FL-500S or equivalent
• Timing chain tensioners (if worn) × 2 — Use OEM Ford specification
• RTV silicone gasket maker × 1 — Motorcraft TA-357

Fluids

• Motorcraft 0W-20 Full Synthetic — 6 qt
• Motorcraft Orange Coolant — 3 qt

Preparation

1. Ensure engine is completely cool (minimum 2 hours after last operation)
2. Disconnect negative battery cable and isolate from terminal
3. Remove engine cover by lifting from rear and pulling forward
4. Drain engine oil completely and remove oil filter
5. Drain coolant from radiator and engine block into appropriate container
6. Remove air intake system from throttle body to air filter housing
7. Label and photograph all electrical connections and vacuum lines before disconnection
8. Support engine from above using engine support bar or hoist

Procedure

1. 1

   Remove valve covers and accessory components
   Remove ignition coils and spark plugs from both cylinder banks. Disconnect wiring harnesses from valve covers. Remove valve cover bolts in reverse of tightening sequence and lift off valve covers. Remove serpentine belt, alternator, A/C compressor (without disconnecting lines), and power steering pump if equipped. Support components aside without stressing hoses.
2. 2

   Remove crankshaft pulley and front accessories
   Using a breaker bar, remove the crankshaft pulley bolt (turning counterclockwise). Use harmonic balancer puller to remove crankshaft pulley from crankshaft snout. Remove any remaining front-mounted accessories or brackets that obstruct access to timing cover. Disconnect coolant hoses from timing cover area.
   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 multiple bolt sizes including 8mm bolts that require specific torque values. Carefully separate timing cover from engine block using plastic pry points only - do not damage aluminum mating surfaces. Remove and discard old timing cover gasket and clean all RTV residue from mating surfaces using gasket scraper and cleaner.
   Torque spec

   Front cover bolts (M8)25 Nm (18 lb-ft)
4. 4

   Verify and mark timing alignment
   Rotate crankshaft to TDC cylinder #1 (compression stroke). Verify timing marks on camshaft sprockets align with cylinder head surface marks and crankshaft keyway points to 12 o'clock position. Use paint pen or marker to mark current positions on all sprockets and chains. Take clear photos showing all timing mark alignments before proceeding.
5. 5

   Install camshaft holding tools
   Install Ford camshaft holding tools into the camshaft slots on both intake and exhaust camshafts for each bank. These tools prevent camshaft rotation during chain removal and ensure proper alignment during reassembly. Verify tools are fully seated and secure.
   ⚠Camshaft holding tools must remain installed until timing chains are reinstalled and tensioned.
6. 6

   Release timing chain tensioners
   Using timing chain tensioner compressor tool, compress both primary and secondary chain tensioners. Lock tensioners in compressed position using retaining pins or lock pins. Remove tensioner mounting bolts and carefully extract tensioners. Inspect tensioners for wear; replace if ratchet mechanism shows signs of slipping or if guide face is grooved.
7. 7

   Remove timing chains and sprockets
   Remove camshaft sprocket bolts from all four camshaft sprockets (two per cylinder bank). Carefully slide timing chains off sprockets along with camshaft sprockets. Remove crankshaft sprocket if needed for access. Keep left and right bank components separated and labeled.
   ⚠️Do not allow camshafts to rotate once chains are removed. Verify holding tools remain secure.
8. 8

   Remove old timing chain guides
   Remove timing chain guide bolts securing both left and right timing chain guides. The guides are mounted to the engine block and cylinder heads. Carefully extract old guides and inspect mounting bosses for cracks or damage. Clean mounting surfaces thoroughly of any debris or old thread locker compound.
   Torque spec

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

   Install new timing chain guides
   Position new timing chain guides in their mounting locations, ensuring proper orientation (guides have specific left/right and top/bottom positions). Apply small amount of clean engine oil to guide surfaces. Install guide bolts finger-tight initially, then torque to specification in a cross-pattern. Verify guides are flush against mounting surfaces with no gaps.
   ℹ️New guides may have protective coating that should be left in place. Do not sand or modify guide surfaces.
   Torque spec

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

    Reinstall timing chains and sprockets
    Install crankshaft sprocket if removed. Route timing chains around new guides and onto crankshaft sprockets according to timing marks. Install camshaft sprockets onto chains and slide onto camshafts, aligning timing marks precisely with reference marks made during disassembly. Verify all colored links or marks on chains align with sprocket marks. Install camshaft sprocket bolts finger-tight.
11. 11

    Install and release tensioners
    Install timing chain tensioners in compressed and locked position. Torque tensioner bolts to specification. Verify all timing marks are still correctly aligned. Remove tensioner lock pins to release tensioners and apply tension to chains. Manually rotate crankshaft two complete revolutions clockwise and recheck all timing marks - they must return to exact alignment.
    ⚠️If timing marks do not realign after two crankshaft rotations, do not proceed. Disassemble and correct timing before continuing.
12. 12

    Torque camshaft sprocket bolts and remove tools
    With timing verified and tensioners active, torque all four camshaft sprocket bolts to specification. Remove camshaft holding tools only after sprocket bolts are fully torqued. Perform final verification of timing mark alignment.
13. 13

    Install timing cover with new gasket
    Install new crankshaft front seal into timing cover if not pre-installed. Apply thin bead of RTV silicone to specified areas of timing cover (refer to service manual for exact locations). Position new timing cover gasket and carefully install timing cover onto engine, ensuring gasket remains properly seated. Install all timing cover bolts in correct locations (note different lengths). Torque 8mm bolts and standard cover bolts to their respective specifications in proper sequence from center outward.
    Torque spec

    Front cover bolts (M8)25 Nm (18 lb-ft)
14. 14

    Reinstall crankshaft pulley and accessories
    Clean crankshaft snout and pulley bore. Install crankshaft pulley and new pulley bolt (if specified). Torque crankshaft pulley bolt to specification. Reinstall power steering pump, A/C compressor, alternator, and all mounting brackets. Install and tension serpentine belt.
    Torque spec

    Crankshaft pulley bolt (stretch, replace)90 Nm (66 lb-ft)
15. 15

    Reinstall valve covers and remaining components
    Install new valve cover gaskets. Position valve covers and install bolts, torquing in proper sequence from center outward. Reinstall spark plugs and ignition coils. Reconnect all electrical connections and vacuum lines per documentation. Install air intake system. Refill engine with specified oil and coolant. Reconnect battery.

Reassembly

1. Double-check all electrical connections are fully seated and secured
2. Verify no tools or parts remain in engine bay before starting
3. Check all fluid levels and top off as necessary before initial start
4. Ensure serpentine belt is properly routed and tensioned

Verification

• Perform initial start and verify no unusual noises from timing chain area - engine should run smoothly without rattles
• Monitor oil pressure gauge during first start - should reach normal pressure within 10 seconds
• Check for oil and coolant leaks around timing cover, valve covers, and all connection points
• Allow engine to reach operating temperature and verify cooling system operates normally
• After 10-minute warm-up cycle, shut off and recheck all fluid levels when cool
• Test drive vehicle and monitor for proper engine performance, smooth idle, and no check engine lights
• After first 50 miles, recheck timing cover area for any seepage and retorque valve cover bolts if specified by manufacturer

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