Timing Chain Tensioner

Replace the timing chain tensioner on the 3.5L EcoBoost V6 engine to restore proper timing chain tension and eliminate rattling or timing issues.

Warnings

Tools required

Parts

• Timing chain tensioner (primary) × 1 — Use OEM Ford specification
• Timing chain tensioner (secondary, if applicable) × 1 — Use OEM Ford specification
• Timing cover gasket/sealant × 1 — Motorcraft TA-357 RTV or equivalent
• Valve cover gaskets × 2 — Use OEM Ford specification
• Crankshaft front seal × 1 — Use OEM Ford specification
• Engine oil × 1 — Motorcraft 0W-20
• Engine coolant × 1 — Motorcraft Orange Coolant

Fluids

• Motorcraft 0W-20 Full Synthetic — 6 qt
• Motorcraft Orange Coolant — 2 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 firmly)
4. Drain engine coolant into suitable container by opening radiator petcock and lower hose
5. Drain engine oil completely
6. Remove both valve covers to access camshaft components
7. Remove accessory drive belt and tensioner
8. Support engine from above using engine support bar or hoist to take load off motor mounts
9. Remove right-side engine mount to allow engine tilt for access

Procedure

1. 1

   Remove crankshaft pulley
   Use crankshaft holding tool to prevent rotation. Remove center bolt using breaker bar and appropriate socket. Use harmonic balancer puller to remove pulley from crankshaft snout without damaging it. Inspect keyway for damage.
2. 2

   Remove timing cover
   Remove all timing cover bolts in reverse of tightening sequence, noting the different bolt lengths and locations. There are both 8mm and smaller bolts. Carefully pry cover away from block using non-marring pry bar at designated pry points. Remove and discard old gasket material and clean all sealing surfaces thoroughly with degreaser and wire brush.
3. 3

   Verify timing alignment
   Rotate crankshaft to TDC (Top Dead Center) for cylinder #1. Verify all timing marks on crankshaft sprocket, camshaft sprockets (both banks), and balance shaft align with their respective marks on the engine block and heads. Take photos for reference before proceeding. Do not proceed if marks do not align perfectly.
   ⚠️All timing marks must align precisely. Proceeding with misaligned timing will destroy the engine.
4. 4

   Install camshaft holding tools
   Install camshaft holding tools on both cylinder banks to prevent camshaft rotation during chain tensioner removal. These tools engage with flats machined on the rear of the camshafts. Verify tools are fully seated and secure.
   ⚠Camshafts must not rotate during this procedure or timing will be lost.
5. 5

   Remove old timing chain tensioner
   Locate the primary timing chain tensioner on the front of the engine block (driver's side). Remove the tensioner mounting bolt. Carefully remove tensioner assembly, controlling spring pressure. If replacing secondary tensioner (passenger side), repeat process. Inspect tensioner face for wear, scoring, or damage. Inspect timing chain guides for wear or cracks.
6. 6

   Inspect timing chains and guides
   With tensioners removed, inspect timing chains for excessive slack, worn links, or damage. Check all timing chain guides (both fixed and moving) for wear grooves, cracks, or missing material. Check sprocket teeth for wear or damage. Replace any worn components now while access is available.
   ℹ️If chain guides show significant wear, replace them now to avoid future failure.
7. 7

   Prepare new tensioner
   Remove new tensioner from packaging. Compress tensioner mechanism using tensioner compression tool or bench vise slowly and carefully. Insert retaining pin or clip through hole to hold tensioner in compressed position. Verify pin is fully seated and tensioner remains compressed.
   ⚠Compress tensioner slowly to avoid damaging internal mechanism. Use proper pins to retain compression.
8. 8

   Install new timing chain tensioner
   Position new tensioner (still in compressed state with pin installed) onto engine block mounting location. Ensure tensioner arm properly engages with timing chain guide. Install mounting bolt and torque to specification. Do NOT remove retaining pin yet. Repeat for secondary tensioner if applicable.
9. 9

   Verify timing and release tensioners
   Double-check all timing marks are still perfectly aligned. Verify camshaft holding tools are still secure. Remove tensioner retaining pin to release tensioner mechanism. The tensioner will apply pressure to the timing chain. Manually rotate crankshaft two complete revolutions clockwise (viewed from front) and verify all timing marks realign perfectly at TDC.
   ⚠️If timing marks do not realign after two revolutions, STOP immediately. Timing is incorrect and must be corrected before proceeding.
10. 10

    Remove camshaft holding tools
    With timing verified correct, carefully remove camshaft holding tools from both cylinder banks. Rotate engine by hand again to verify smooth operation and correct timing mark alignment. Check for any binding or unusual resistance.
11. 11

    Install new timing cover seal and gasket
    Install new crankshaft front seal into timing cover using seal driver, ensuring it seats evenly and fully. Apply thin continuous bead of RTV silicone sealant to timing cover mating surface per Ford service procedure (specific pattern required). Allow sealant to set for time specified by sealant manufacturer before installing cover.
    ℹ️Use only specified RTV sealant. Incorrect sealant can cause oil leaks or block oil passages.
12. 12

    Reinstall timing cover
    Carefully position timing cover onto engine block, ensuring proper alignment with dowel pins. Install all timing cover bolts finger-tight, noting correct bolt lengths and positions. Tighten bolts in specified sequence, starting with 8mm bolts to their torque specification, then smaller bolts to their specification. Do not overtighten.
13. 13

    Reinstall crankshaft pulley
    Clean crankshaft snout and pulley hub thoroughly. Align pulley keyway with crankshaft key and slide pulley onto snout. Install new crankshaft pulley bolt (recommended). Use holding tool to prevent crankshaft rotation and torque bolt to specification. Some procedures require additional angle torque - verify with Ford service data.
14. 14

    Reinstall valve covers and remaining components
    Install new valve cover gaskets. Position valve covers and install bolts finger-tight. Torque valve cover bolts in specified sequence from center outward. Reinstall right engine mount and torque fasteners. Remove engine support. Reinstall accessory drive belt and tensioner. Reinstall engine cover.
15. 15

    Refill fluids and final checks
    Refill engine with 6 quarts of Motorcraft 0W-20 synthetic oil. Refill cooling system with Motorcraft Orange coolant, burping system to remove air pockets. Reconnect negative battery cable. Start engine and verify oil pressure immediately. Check for oil or coolant leaks around timing cover and valve covers. Allow engine to reach operating temperature and recheck fluid levels.
    ⚠Monitor oil pressure gauge immediately upon startup. Shut down immediately if no pressure is indicated.

Reassembly

1. Torque all fasteners to exact specifications in proper sequence
2. Use new gaskets and seals throughout - do not reuse old components
3. Apply RTV sealant sparingly and in correct pattern to avoid blocking oil passages
4. Verify all timing marks align perfectly before buttoning up engine
5. Double-check all electrical connections and hoses are reconnected

Verification

• Start engine and verify immediate oil pressure on gauge
• Listen for any abnormal timing chain noise, rattling, or ticking from front of engine
• Allow engine to idle and reach operating temperature, monitoring for leaks
• Check for oil leaks around timing cover and valve covers
• Check for coolant leaks around timing cover lower edge
• Verify engine runs smoothly without misfires or rough idle
• Test drive vehicle and verify normal power delivery and smooth operation under load
• Recheck oil and coolant levels after test drive when engine is cold

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