Complete replacement of a single piston assembly in the 3.5L EcoBoost V6, requiring removal of cylinder head, connecting rod, and piston from the affected cylinder.

Warnings

Tools required

Parts

• Piston assembly with rings × 1 — Use OEM specification
• Connecting rod bearings (set) × 1 — Use OEM specification
• Cylinder head gasket × 1 — Use OEM specification
• Connecting rod bolts (TTY) × 2 — Use OEM specification
• Cylinder head bolt set (TTY) × 1 — Use OEM specification
• Valve cover gasket × 1 — Use OEM specification
• Oil pan gasket × 1 — Use OEM specification
• Turbocharger gasket set × 1 — Use OEM specification
• Timing chain tensioner × 1 — Use OEM specification
• Timing cover gasket × 1 — Use OEM specification
• Oil filter × 1 — FL-910S or equivalent
• Oil drain plug crush washer × 1 — Use OEM specification
• Intake manifold gaskets × 1 — Use OEM specification
• Exhaust manifold gaskets × 1 — Use OEM specification

Fluids

• Motorcraft 0W-20 Full Synthetic — 6 qt
• Motorcraft Orange Coolant — 13 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. Drain engine coolant completely into appropriate container using radiator drain valve and engine block drain plugs
4. Drain engine oil and remove oil filter
5. Remove engine cover and air intake system including both turbocharger inlet pipes
6. Relieve fuel system pressure by removing fuel pump fuse and cranking engine until it stalls
7. Document all electrical connector positions and hose routing with photos
8. Remove front bumper cover and intercooler assembly for access
9. Support engine with hoist or support fixture from above
10. Mark cylinder location being serviced and verify identification before disassembly

Procedure

1. 1

   Remove intake and exhaust systems
   Disconnect throttle body and remove complete intake manifold assembly. Remove both turbochargers with exhaust manifolds as complete units. Label all vacuum lines, PCV hoses, and electrical connections for reinstallation. Remove charge air cooler pipes and intercooler plumbing.
2. 2

   Remove valve cover and accessory components
   Disconnect ignition coils and remove all six coil packs from the affected bank. Remove fuel rail with injectors as an assembly. Unbolt and remove valve cover from the cylinder bank containing the damaged piston. Remove any interfering components such as wiring harnesses or coolant hoses.
   Torque spec

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

   Remove timing components
   Rotate engine to TDC on cylinder #1. Remove crankshaft pulley using appropriate puller. Remove timing chain cover and timing chain tensioners. Mark timing chain position relative to camshaft and crankshaft sprockets. Remove timing chain from the affected bank. Install camshaft locking tools to prevent valve damage.
   Torque spec

   Gasket Bolts23 Nm (17 lb-ft)
4. 4

   Remove cylinder head
   Remove cylinder head bolts in reverse of tightening sequence (consult factory service manual for exact pattern). Carefully lift cylinder head from engine block using lifting brackets. Place head on clean padded surface. Inspect head gasket for failure pattern to confirm affected cylinder. Clean all gasket surfaces thoroughly without damaging aluminum.
5. 5

   Remove oil pan and oil pump pickup
   Raise vehicle on lift. Remove all oil pan bolts and carefully separate pan from engine block. Remove oil pump pickup tube mounting bolts. This provides access to connecting rod bolts from below.
   Torque spec

   Oil Pan Bolts12 Nm (9 lb-ft)
6. 6

   Remove cylinder ridge and piston assembly
   Use ridge reamer to remove any ridge at top of cylinder bore where piston rings have not contacted. Rotate crankshaft to position affected piston at bottom dead center. Mark connecting rod and cap orientation with punch marks. Remove connecting rod cap bolts and cap. Push piston and connecting rod assembly up and out through top of engine block. Keep rod cap with original rod.
   ⚠Failure to remove cylinder ridge will cause piston ring breakage during removal. Ridge must be completely removed before piston extraction.
7. 7

   Inspect and measure cylinder bore
   Clean cylinder bore thoroughly with solvent and lint-free cloth. Using inside micrometer or bore gauge, measure cylinder diameter at top, middle, and bottom in two perpendicular directions. Check for taper, out-of-round, and scoring. Maximum allowable taper is 0.002 inches, out-of-round is 0.001 inches. If beyond limits, cylinder must be honed or block replaced.
   ℹ️Record all measurements. Compare to factory specifications. Cylinder must be within tolerance for proper piston-to-bore clearance.
8. 8

   Prepare connecting rod and inspect crankshaft journal
   Remove old piston from connecting rod by pressing out wrist pin (if reusing rod). Clean connecting rod thoroughly and inspect for cracks using magnetic particle inspection if available. Measure crankshaft journal diameter and out-of-round condition. Journal must be within 0.0005 inches roundness. Install new connecting rod bearings in rod and cap.
   ⚠If connecting rod is bent or damaged, it must be replaced. A bent rod will cause premature engine failure.
9. 9

   Install piston rings and measure ring gaps
   Install new piston rings on new piston using ring expander tool. Before installation, place each ring in cylinder bore and measure end gap with feeler gauge. Top compression ring gap should be 0.010-0.020 inches, second ring 0.010-0.020 inches, oil ring 0.015-0.055 inches. Stagger ring gaps 120 degrees apart. Top ring gap should not align with piston pin or thrust side.
   ⚠Incorrect ring gap can cause ring breakage and engine failure. All gaps must be within specification before installation.
10. 10

    Install piston assembly into cylinder
    Coat piston, rings, and cylinder bore with assembly lubricant. Install connecting rod to piston with new wrist pin ensuring directional markings face forward. Install piston ring compressor around piston. Carefully guide piston into cylinder bore from top while guiding connecting rod from below. Ensure piston directional arrow faces front of engine. Tap piston gently with wooden hammer handle until fully seated.
    ⚠Do not force piston into bore. Rings must be fully compressed in ring compressor. Forcing can break rings or damage piston.
11. 11

    Install connecting rod cap and check bearing clearance
    Place Plastigage across crankshaft journal. Install connecting rod cap with new TTY bolts in correct orientation matching punch marks. Torque connecting rod bolts to 45 Nm (33 lb-ft), then rotate an additional 90 degrees using angle gauge. Remove cap and measure Plastigage width. Clearance should be 0.0008-0.0015 inches. If outside specification, determine cause before proceeding.
    ⚠️Connecting rod bolts are TTY and must be replaced. Never reuse old bolts. Do not rotate crankshaft with Plastigage installed.
    Torque spec

    Connecting Rod Bolts45 Nm (33 lb-ft)
12. 12

    Reinstall oil pump pickup and oil pan
    Clean all gasket surfaces on oil pan and engine block. Install new oil pan gasket. Position oil pump pickup tube and torque mounting bolts to specification. Install oil pan and torque bolts in sequence from center outward to 12 Nm (9 lb-ft). Install new oil drain plug with new crush washer and torque to 35 Nm (26 lb-ft).
    Torque spec

    Oil Pan Bolts12 Nm (9 lb-ft)

    Oil Drain Plug35 Nm (26 lb-ft)
13. 13

    Install cylinder head with new gasket
    Position new cylinder head gasket on engine block ensuring all alignment dowels are properly located. Carefully lower cylinder head onto block. Install new TTY cylinder head bolts and hand tighten. Following factory tightening sequence, torque all bolts to 65 Nm (48 lb-ft). Then rotate each bolt an additional 90 degrees, followed by a final 90 degrees (total 180 degrees after torque).
    ⚠️Cylinder head bolt sequence and TTY rotation must be followed exactly. Incorrect procedure will result in head gasket failure or head warping.
    Torque spec

    Cylinder Head Bolts65 Nm (48 lb-ft)
14. 14

    Reinstall timing components
    Align timing chain marks to camshaft and crankshaft sprockets per factory specifications. Install timing chain ensuring proper tensioner engagement. Install new timing chain tensioners and release locking mechanisms. Verify timing alignment by rotating engine two complete revolutions by hand. Reinstall timing cover with new gasket and torque bolts to specification.
    ⚠️Incorrect timing will cause catastrophic valve-to-piston contact and engine destruction. Verify timing marks three times before proceeding.
    Torque spec

    Gasket Bolts23 Nm (17 lb-ft)
15. 15

    Reinstall remaining components
    Install valve cover with new gasket and torque cover bolts to 19 Nm (14 lb-ft). Reinstall fuel rail, ignition coils, intake manifold with new gaskets torquing gasket bolts to 23 Nm (17 lb-ft). Reinstall turbochargers and exhaust components. Reconnect all electrical connectors, vacuum lines, and hoses per documentation. Install intercooler system and air intake. Refill cooling system with 13 quarts Motorcraft Orange Coolant. Install new oil filter and fill with 6 quarts Motorcraft 0W-20 synthetic oil.
    Torque spec

    Cover Bolts19 Nm (14 lb-ft)

    Gasket Bolts23 Nm (17 lb-ft)

Reassembly

1. Double-check all electrical connectors are fully seated and locked
2. Verify all coolant hoses are clamped securely and vacuum lines are connected
3. Confirm turbocharger oil feed and drain lines are properly installed and torqued
4. Ensure all timing marks were verified and timing chain tensioners are properly engaged
5. Check that engine oil level is correct on dipstick after filling
6. Reconnect negative battery cable

Verification

• Prime oil system by cranking engine with fuel pump fuse removed until oil pressure registers on gauge (typically 5-10 seconds)
• Start engine and verify oil pressure reaches normal range within 5 seconds
• Check for any coolant, oil, or fuel leaks while engine is running
• Allow engine to reach normal operating temperature and verify cooling fans cycle properly
• Monitor for unusual noises such as knocking, ticking, or rattling from rebuilt cylinder
• Check for exhaust leaks at turbocharger and manifold connections
• Perform test drive under light load and verify smooth operation without misfires
• Scan for diagnostic trouble codes using OBD-II scanner
• Recheck oil level after engine cools and top off if necessary
• Retorque cylinder head bolts after 500 miles per manufacturer cold torque specification if required by service manual

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