This procedure replaces the valve stem seals on the 3.5L EcoBoost V6 engine to address oil consumption or smoking issues without removing the cylinder heads.

Warnings

Tools required

Parts

• Valve stem seal set (24 seals) × 1 — Use OEM specification
• Valve cover gasket set (left and right) × 1 — Use OEM specification
• Spark plugs × 6 — Motorcraft SP-546 or equivalent
• Ignition coil boot set × 6 — Use OEM specification
• Valve cover bolt grommets × 1 — Use OEM specification
• Engine oil and filter × 1 — Use OEM specification
• RTV gasket maker (high-temp) × 1 — Motorcraft TA-357 or equivalent
• Anti-seize compound × 1 — Use OEM specification

Fluids

• Motorcraft 5W-20 Synthetic Blend engine oil — 6 qt

Preparation

1. Ensure engine is completely cold before beginning work
2. Disconnect negative battery cable and wait 10 minutes for airbag system to discharge
3. Remove engine cover by pulling upward on retaining clips
4. Relieve fuel system pressure by removing fuel pump fuse and running engine until it stalls
5. Drain engine coolant into appropriate container
6. Position vehicle on level surface with parking brake engaged
7. Gather all special tools and verify availability before starting disassembly
8. Take photos of all harness routing, vacuum lines, and component positions for reference during reassembly

Procedure

1. 1

   Remove intake and accessory components
   Remove air intake system including air filter box and intake tube. Disconnect all electrical connectors from ignition coils, sensors, and fuel injectors. Label each connector for reassembly. Remove throttle body and charge air cooler tubes. Disconnect PCV hoses and vacuum lines from both valve covers. Remove the upper intake manifold assembly by disconnecting all sensors and removing mounting hardware. Tag all wiring and hoses for proper reinstallation.
2. 2

   Remove valve covers
   Disconnect ignition coils from both banks and remove them. Remove valve cover bolts in reverse of tightening sequence (outside to inside). Carefully lift valve covers away from cylinder heads. If covers are stuck, gently tap with plastic mallet - do not pry against sealing surfaces. Clean all gasket material from valve cover and cylinder head mating surfaces using plastic scrapers only. Inspect valve cover bolt grommets and replace if damaged.
3. 3

   Verify and mark camshaft timing
   Rotate crankshaft to bring cylinder 1 to TDC on compression stroke. Both camshaft timing marks should align with their respective marks on the cylinder head. Use timing pins or alignment tools specific to 3.5L EcoBoost to lock camshafts in position. Mark timing chain position relative to camshaft sprockets using paint pen. Take detailed photos of timing chain alignment and all timing marks. This is critical for reassembly verification.
   ⚠Verify timing alignment on BOTH cylinder banks before proceeding. Misalignment indicates timing issue that must be corrected first.
4. 4

   Remove camshafts from Bank 1 (passenger side)
   Remove camshaft position sensor. Loosen camshaft cap bolts in reverse sequence (outside to inside) in multiple passes, no more than 1/4 turn per pass to prevent warping. Keep all camshaft caps in order and oriented correctly - they are position-specific and directional. Carefully lift camshafts straight up and place on clean surface. Keep intake and exhaust camshafts separate and labeled. Inspect camshaft journals and lobes for wear or damage.
5. 5

   Remove spark plugs and prepare for valve seal replacement on Bank 1
   Remove all spark plugs from Bank 1 cylinders and inspect for condition. Keep them in order if reusing. Install air hose adapter into spark plug hole of first cylinder to be serviced. Connect shop air (90+ PSI minimum) to adapter. The air pressure will hold valves in place during spring compression. Verify air pressure is holding by listening for leaks. If air leaks excessively from adjacent cylinders or crankcase, piston may not be at proper position - rotate crankshaft slightly to seal rings.
   ⚠️Ensure air pressure is stable before compressing valve springs. Loss of pressure during keeper removal will drop valve into cylinder.
6. 6

   Replace valve seals on Bank 1 cylinders
   Using overhead cam valve spring compressor, carefully compress valve spring on first valve. Remove valve keepers using magnetic tool or needle-nose pliers - they are small and easily lost. Release spring compressor and remove valve spring retainer and valve spring. Note orientation of all components. Use appropriate tool to remove old valve seal - they may be tight. Install new valve seal using installation tool, ensuring it seats fully and squarely on valve guide. Do not hammer directly on seal. Reinstall valve spring, retainer, and compress spring. Install valve keepers ensuring they seat properly in valve stem grooves. Slowly release compressor and verify keepers are locked in place by gently tapping valve stem with plastic tool. Repeat for all valves on Bank 1 (12 valves total - 2 per cylinder). Maintain air pressure on each cylinder during its valve service.
   ⚠️Verify valve keepers are fully seated after installation. Tap valve stem gently to confirm - keepers must not dislodge or valve will drop when engine runs.
7. 7

   Reinstall Bank 1 camshafts
   Thoroughly clean camshaft journals and cylinder head camshaft bearing surfaces. Apply clean engine oil to all camshaft lobes and journals. Position camshafts in cylinder head with timing marks in correct alignment as documented earlier. Install camshaft caps in correct positions and orientation - they are numbered and marked for location. Apply clean engine oil to camshaft cap bolt threads. Install and tighten camshaft cap bolts in sequence from center outward in multiple passes to specified torque. First pass: finger tight. Second pass: 7 Nm. Final pass: 14 Nm. Verify camshafts rotate smoothly by hand after installation.
   Torque spec

   Camshaft Cap Bolts14 Nm (10 lb-ft)
8. 8

   Remove camshafts from Bank 2 (driver side)
   Repeat camshaft removal process for Bank 2. Remove camshaft position sensor. Loosen camshaft cap bolts in reverse sequence in multiple passes, no more than 1/4 turn per pass. Keep all camshaft caps in order and oriented correctly. Carefully lift camshafts straight up and place on clean surface. Keep intake and exhaust camshafts separate and labeled. This bank may require removal of additional components for access depending on specific vehicle configuration.
9. 9

   Replace valve seals on Bank 2 cylinders
   Remove all spark plugs from Bank 2 cylinders. Install air hose adapter into spark plug hole of first cylinder to be serviced. Connect shop air (90+ PSI minimum). Using overhead cam valve spring compressor, compress valve spring on first valve. Remove valve keepers using magnetic tool. Release spring compressor and remove valve spring retainer and valve spring. Remove old valve seal. Install new valve seal using installation tool, ensuring full seating. Reinstall valve spring, retainer, compress spring, and install valve keepers. Verify keepers are locked in place. Repeat for all valves on Bank 2 (12 valves total). Work systematically through each cylinder maintaining air pressure during service.
   ⚠️Do not rush this process. Each valve keeper installation must be verified before moving to next valve.
10. 10

    Reinstall Bank 2 camshafts and verify timing
    Clean camshaft journals and cylinder head bearing surfaces. Apply clean engine oil to all camshaft lobes and journals. Position camshafts in cylinder head with timing marks in correct alignment. Install camshaft caps in correct positions. Apply clean engine oil to camshaft cap bolt threads. Tighten camshaft cap bolts in sequence from center outward in multiple passes: finger tight, 7 Nm, then final torque of 14 Nm. Verify camshafts rotate smoothly. Remove timing pins/alignment tools and verify timing marks align correctly on both banks. Manually rotate engine two complete revolutions by crankshaft and recheck all timing marks for proper alignment.
    ⚠Timing verification is mandatory. If marks do not align after rotation, timing chain position must be corrected before proceeding.
    Torque spec

    Camshaft Cap Bolts14 Nm (10 lb-ft)
11. 11

    Install new spark plugs
    Apply small amount of anti-seize compound to spark plug threads, avoiding electrode area. Install new spark plugs by hand, ensuring they thread smoothly without cross-threading. Torque spark plugs to specification using torque wrench. Over-torquing can strip aluminum threads; under-torquing can cause blown plugs. Install ignition coils with new boots if needed and secure with mounting hardware.
    Torque spec

    Spark Plugs - Aluminum Head20 Nm (15 lb-ft)
12. 12

    Install valve covers
    Install new valve cover gaskets on valve covers - do not reuse old gaskets. Apply small bead of RTV sealant at camshaft cap to cylinder head joints (front and rear positions only) as specified in service manual. Position valve covers carefully on cylinder heads. Install new valve cover bolt grommets if equipped. Install valve cover bolts and tighten in sequence from center outward to specified torque. Do not overtighten as this will distort cover and cause leaks.
    Torque spec

    Cover Bolts19 Nm (14 lb-ft)
13. 13

    Reinstall intake manifold and accessories
    Reinstall upper intake manifold with new gaskets if required. Torque manifold mounting bolts to specification per service manual. Reconnect all vacuum lines, PCV hoses, and electrical connectors using photos and labels from disassembly. Install charge air cooler tubes and throttle body. Reconnect fuel injector connectors and all sensor harnesses. Install air intake system including filter box and intake tube. Double-check all connections are secure.
14. 14

    Refill fluids and prepare for startup
    Refill cooling system with specified Motorcraft Orange Coolant. Replace engine oil and filter with Motorcraft 5W-20 Synthetic Blend (6 quarts total). Reconnect negative battery cable. Reinstall engine cover. Prime fuel system by cycling ignition on/off several times without starting. Check for any fuel, coolant, or oil leaks before starting engine.

Reassembly

1. Verify all electrical connectors are fully seated and locked
2. Confirm all vacuum lines and PCV hoses are properly routed and connected
3. Double-check torque on all critical fasteners including camshaft caps and valve covers
4. Ensure no tools or parts are left in engine bay
5. Verify air intake system is fully assembled and sealed
6. Check engine oil level on dipstick after filling

Verification

• Start engine and monitor for unusual noises, particularly valve train noise which should be minimal
• Check for oil leaks at valve covers - address immediately if found
• Check for coolant and vacuum leaks
• Allow engine to reach operating temperature and verify no smoke from exhaust (may smoke briefly from residual oil)
• Monitor oil consumption over next 500 miles to verify seal effectiveness
• Check for diagnostic trouble codes related to camshaft position or timing
• Perform test drive and verify normal engine performance and power
• Recheck oil level after test drive and top off if needed
• Inspect valve covers for leaks after engine cools down

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