This procedure adjusts valve lash on the 3.5L EcoBoost engine to maintain proper valve train clearances and optimize engine performance.

Warnings

Tools required

Parts

• Left valve cover gasket × 1 — Motorcraft VC-4606 or equivalent
• Right valve cover gasket × 1 — Motorcraft VC-4607 or equivalent
• Spark plug tube seals × 6 — Use OEM specification

Preparation

1. Ensure engine is completely cold (not run for at least 4 hours)
2. Disconnect negative battery cable
3. Remove engine appearance cover
4. Remove air intake system components to access valve covers
5. Label and disconnect ignition coils and electrical connectors from both valve covers
6. Remove ignition coils from all six cylinders
7. Photograph or label all vacuum lines and PCV connections before removal

Procedure

1. 1

   Remove right valve cover
   Unbolt and remove the right (passenger side) valve cover. Remove bolts in reverse of tightening sequence, working from outside toward center. Carefully lift cover away from cylinder head, noting position of any wiring harness clips or brackets attached to the cover.
   Torque spec

   Cover Bolts19 Nm (14 lb-ft)
2. 2

   Remove left valve cover
   Unbolt and remove the left (driver side) valve cover. Remove bolts in reverse of tightening sequence. This side may require additional component removal for access. Carefully lift cover away from cylinder head.
   Torque spec

   Cover Bolts19 Nm (14 lb-ft)
3. 3

   Rotate engine to TDC cylinder 1
   Using a 22mm socket on the crankshaft bolt or engine rotation tool, rotate the engine clockwise (viewed from front) until cylinder 1 is at top dead center on compression stroke. Verify both intake and exhaust rocker arms on cylinder 1 have clearance (cam lobes pointing away). The timing marks on the front cover should align.
   ⚠Always rotate engine in normal direction of rotation (clockwise from front). Never rotate backwards as this can damage timing chain tensioners.
4. 4

   Check valve lash on bank 1
   With cylinder 1 at TDC compression, check and record valve lash on cylinders 1, 2, and 3 (right bank). Insert feeler gauge between rocker arm and valve stem. Intake specification is 0.008-0.010 inch, exhaust is 0.010-0.012 inch. The feeler gauge should slide with slight drag when clearance is correct. Mark any valves requiring adjustment.
   ℹ️Front of engine: cylinder 1 is forward-most on passenger side, cylinder 4 forward-most on driver side. Cylinder arrangement: Right bank 1-2-3, Left bank 4-5-6.
5. 5

   Adjust out-of-spec valves on bank 1
   For any valve lash out of specification, loosen the lock nut while holding the adjusting screw with valve adjustment tool. Turn adjusting screw until proper clearance is achieved with feeler gauge. Hold screw stationary and tighten lock nut to specification. Recheck clearance after tightening and readjust if necessary.
   ⚠The adjusting screw can turn while tightening lock nut. Always hold screw with adjustment tool and recheck clearance after tightening.
   Torque spec

   Valve Lash Adjusting Screw Lock Nut20 Nm (15 lb-ft)
6. 6

   Rotate engine 360 degrees
   Rotate the crankshaft one full turn (360 degrees) clockwise. This brings cylinder 4 to TDC on compression stroke. Verify both rocker arms on cylinder 4 have clearance.
7. 7

   Check valve lash on bank 2
   With cylinder 4 at TDC compression, check and record valve lash on cylinders 4, 5, and 6 (left bank). Use same feeler gauge technique and specifications as bank 1. Mark any valves requiring adjustment.
8. 8

   Adjust out-of-spec valves on bank 2
   Adjust any out-of-specification valves on the left bank using same procedure as bank 1. Loosen lock nut while holding adjusting screw, adjust clearance, then torque lock nut while holding screw. Verify clearance after each adjustment.
   Torque spec

   Valve Lash Adjusting Screw Lock Nut20 Nm (15 lb-ft)
9. 9

   Clean valve cover mating surfaces
   Thoroughly clean both valve cover mating surfaces and cylinder head sealing surfaces. Remove all old gasket material using plastic scraper. Clean surfaces with brake cleaner and allow to dry completely. Inspect for warping or damage.
   ⚠Do not use metal scrapers on aluminum cylinder heads. Use only plastic scrapers to avoid gouging sealing surfaces.
10. 10

    Install new gaskets and valve covers
    Install new valve cover gaskets and spark plug tube seals in valve covers. Ensure gaskets are properly seated in cover grooves. Install left valve cover first, then right valve cover. Start all bolts finger-tight before torquing. Tighten valve cover bolts in sequence (center outward pattern) to specification.
    ⚠Valve cover bolts must be tightened in proper sequence to avoid gasket leaks. Overtightening can crack valve covers.
    Torque spec

    Cover Bolts19 Nm (14 lb-ft)
11. 11

    Reinstall ignition coils and electrical connections
    Install all six ignition coils with new O-rings if equipped. Reconnect all electrical connectors, ensuring proper seating. Reinstall PCV system components, vacuum lines, and any wiring harness clips removed during disassembly.

Reassembly

1. Reinstall air intake system components
2. Reinstall engine appearance cover
3. Reconnect negative battery cable
4. Verify all tools and shop towels are removed from engine compartment

Verification

• Start engine and verify no oil leaks from valve covers
• Listen for abnormal valve train noise during warm-up
• Allow engine to reach operating temperature and verify smooth idle
• Check for diagnostic trouble codes related to ignition or cam/crank correlation
• Recheck valve cover area for leaks after first drive cycle

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