Complete piston ring replacement on all six cylinders of the 3.5L EcoBoost V6 engine, requiring full engine disassembly including cylinder head and crankshaft removal.

Warnings

Tools required

Parts

• Piston ring set - all 6 cylinders × 1 — Use OEM specification
• Cylinder head gasket set × 2 — Use OEM specification
• Valve cover gaskets × 2 — Use OEM specification
• Turbocharger gaskets × 2 — Use OEM specification
• Oil pan gasket × 1 — Use OEM specification
• Timing cover gasket × 1 — Use OEM specification
• Timing chain set (if wear detected) × 1 — Use OEM specification
• Main bearing set (if clearances out of spec) × 1 — Use OEM specification
• Rod bearing set (if clearances out of spec) × 1 — Use OEM specification
• Oil filter × 1 — FL-910S or equivalent
• Oil drain plug crush washer × 1 — Use OEM specification
• Connecting rod bolts (TTY) × 1 — Use OEM specification
• Main bearing cap bolts (TTY) × 1 — Use OEM specification
• Cylinder head bolts (TTY) × 2 — Use OEM specification
• Exhaust manifold gaskets × 2 — Use OEM specification
• Water pump gasket/O-rings × 1 — Use OEM specification
• Thermostat and O-ring × 1 — Use OEM specification
• RTV silicone gasket maker × 2 — Motorcraft TA-31

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 15 minutes for airbag system to discharge
3. Drain engine oil completely and remove oil filter
4. Drain cooling system completely from radiator and block drain points
5. Remove engine cover and air intake system
6. Disconnect all electrical connectors, labeling each for reassembly
7. Remove both turbochargers and intercooler piping
8. Disconnect fuel lines (relieve fuel pressure first by removing fuel pump fuse and running engine until it stalls)
9. Disconnect coolant hoses, heater hoses, and vacuum lines
10. Remove serpentine belt and accessory drive components as needed
11. Disconnect exhaust system at manifolds
12. Remove transmission-to-engine bolts and support transmission with jack
13. Attach engine hoist with chains to factory lift points
14. Remove engine mount bolts and carefully lift engine from vehicle
15. Mount engine securely on engine stand
16. Set up clean workspace with parts organization system

Procedure

1. 1

   Remove Valve Covers and Timing Components
   Remove both valve covers. Remove timing chain cover, noting RTV application points. Lock camshafts in position using camshaft holding tools. Mark timing chain alignment on sprockets and chain. Remove timing chain tensioners, guides, and chains. Remove camshaft sprockets and phaser assemblies. Document all alignment marks with photos.
2. 2

   Remove Cylinder Heads
   Remove cylinder head bolts in reverse of tightening sequence (consult service manual for exact sequence). Carefully lift cylinder heads off block, using plastic pry points only if needed. Place heads on clean surface with combustion chambers facing up. Remove and discard head gaskets. Cover open cylinders with clean shop towels to prevent debris entry.
3. 3

   Remove Oil Pan and Oil Pump
   Remove oil pan bolts in reverse sequence and carefully separate oil pan from block. Remove oil pump pickup tube. Remove oil pump assembly from front of block. Inspect oil pump for wear; replace if needed. Clean all gasket surfaces thoroughly.
4. 4

   Inspect Cylinders and Remove Ridge
   Rotate crankshaft to position each piston at bottom dead center. Use ridge reamer to carefully remove ridge at top of each cylinder bore where piston rings have not traveled. Remove only the ridge, not material from unworn bore area. Clean cylinders thoroughly after reaming. Measure cylinder bore diameter at top, middle, and bottom in two directions (parallel and perpendicular to crankshaft). Record all measurements. Maximum allowable taper is 0.05mm; out-of-round limit is 0.03mm. If beyond limits, cylinders require boring and oversize pistons.
   ⚠Ridge must be completely removed before attempting to remove pistons or ring lands will catch on ridge and break.
5. 5

   Remove Connecting Rod Caps and Pistons
   Mark each connecting rod and cap with cylinder number using punch marks or permanent marker. Mark orientation (front of engine). Remove connecting rod cap bolts and caps, keeping each cap with its rod. Install rod bolt protectors or short lengths of vacuum hose over rod bolts to prevent crankshaft journal damage. Push each piston/rod assembly up and out through top of cylinder. Keep all components organized by cylinder number.
   ⚠Never mix pistons, rods, or caps between cylinders. Each must return to its original location.
6. 6

   Remove Old Piston Rings
   Using piston ring expander tool, carefully expand and remove each ring starting from top ring down. Remove top compression ring, second compression ring, then oil control ring assembly (top rail, spacer, bottom rail). Inspect ring grooves for damage, carbon buildup, or excessive wear. Clean ring grooves thoroughly using ring groove cleaner, removing all carbon deposits. Inspect pistons for cracks, scuffing, or scoring. Check piston skirt for wear. Measure piston-to-bore clearance if specifications are available.
7. 7

   Inspect Rod Bearings and Crankshaft
   Remove main bearing caps, marking each cap and orientation. Lift crankshaft from block and place on clean surface. Inspect all rod bearing and main bearing surfaces for scoring, discoloration, or wear patterns. Inspect crankshaft journals for scoring, out-of-round, or taper. Measure all journals with micrometer. Check crankshaft end play. If any wear is beyond specification, crankshaft must be reground and undersize bearings installed. Clean crankshaft thoroughly, including oil passages using brake cleaner and compressed air.
   ℹ️This is an ideal time to replace bearings as a precautionary measure since engine is fully disassembled.
8. 8

   Clean and Inspect Block
   Thoroughly clean engine block including all cylinder bores, deck surfaces, and oil passages. Use brake cleaner and compressed air. Remove all traces of old gasket material. Inspect block deck surface for warpage using precision straightedge and feeler gauge. Maximum allowable warpage is 0.05mm. Inspect cylinder walls for scoring or damage. Ensure all cylinder bores are clean and dry before assembly.
9. 9

   Install Crankshaft and Main Bearings
   Install main bearing inserts in block and bearing caps, ensuring bearing tabs engage correctly. Lubricate bearings and crankshaft journals with assembly lube. Carefully lower crankshaft into block. Install upper main bearing inserts. Apply assembly lube to all bearing surfaces. Install main bearing caps in correct orientation and sequence. Install new TTY main bearing cap bolts. Torque main bearing cap bolts to 75 Nm (55 lb-ft) in proper sequence, then tighten additional angle as specified in service manual (typically 90 degrees). Verify crankshaft rotates freely. Check crankshaft end play with dial indicator.
   ⚠Main bearing cap bolts are torque-to-yield. Use new bolts only and follow torque plus angle procedure exactly.
   Torque spec

   Main Bearing Cap Bolts75 Nm (55 lb-ft)
10. 10

    Install New Piston Rings
    Check piston ring end gap by inserting each ring into corresponding cylinder bore (push ring square with piston) and measuring gap with feeler gauge. Typical specification is 0.25-0.45mm for top ring, 0.30-0.50mm for second ring. If gap is too tight, file ring end carefully. Install oil control ring first: install lower rail, then spacer, then upper rail. Ensure rails are properly seated in groove and spacer ends do not overlap. Install second compression ring with mark facing up. Install top compression ring with mark facing up. Stagger ring end gaps 120 degrees apart, none aligned with piston pin bore.
    ⚠Installing rings upside down or with incorrect end gap alignment will cause excessive oil consumption and potential ring failure.
11. 11

    Install Pistons and Connecting Rods
    Install connecting rod bearing inserts in rods and caps. Apply assembly lube to rod bearings and crankshaft rod journals. Install rod bolt protectors. Lubricate piston rings and cylinder walls with clean engine oil. Orient piston correctly for its cylinder (mark on piston crown faces front). Install piston ring compressor and compress rings fully. Guide piston/rod assembly into correct cylinder, ensuring rod orientation is correct. Gently tap piston down with wooden handle until it enters bore, then carefully push down until rod bearing seats on crankshaft journal. Remove rod bolt protectors. Install rod cap in correct orientation. Install new TTY rod bolts and torque to 45 Nm (33 lb-ft), then tighten additional angle per service manual (typically 90 degrees). Repeat for all six pistons. Verify crankshaft rotates freely after each piston installation.
    ⚠Connecting rod bolts are torque-to-yield. Use new bolts only and follow torque plus angle procedure.
    ⚠Never force piston into bore. If resistance is felt, remove and check for ring not fully compressed or misaligned.
    Torque spec

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

    Install Oil Pump and Oil Pan
    Install oil pump to front of block with new gasket. Torque oil pump mounting bolts to 23 Nm (17 lb-ft) per specification. Install oil pump pickup tube with new O-ring and torque to 12 Nm (9 lb-ft). Apply thin bead of RTV silicone to oil pan mating surface per service manual specifications. Install new oil pan gasket. Position oil pan and install bolts finger tight. Torque oil pan bolts to 12 Nm (9 lb-ft) in proper sequence (center outward pattern). Allow RTV to cure per manufacturer specifications before filling with oil.
    Torque spec

    Oil Pump Pickup Tube12 Nm (9 lb-ft)

    Oil Pan Bolts12 Nm (9 lb-ft)
13. 13

    Install Cylinder Heads
    Clean cylinder head mating surfaces and block deck thoroughly. Ensure surfaces are completely clean and dry. Install new head gaskets on block, ensuring correct orientation (check for UP marks and front orientation). Carefully lower cylinder heads onto block, aligning dowel pins. Install new TTY cylinder head bolts, lightly oiled under head and on threads. Torque cylinder head bolts to 65 Nm (48 lb-ft) in proper sequence per service manual, then tighten additional angle as specified (typically two stages of 90 degrees each for total of 180 degrees). Follow exact sequence and procedure from service manual.
    ⚠️Cylinder head bolt sequence and torque-to-yield procedure is critical. Improper installation will cause head gasket failure and potential engine damage.
    Torque spec

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

    Install Timing Components
    Rotate crankshaft to TDC cylinder #1. Install camshafts in cylinder heads if removed, ensuring correct timing position. Install camshaft phaser assemblies and sprockets. Install timing chains with all alignment marks properly positioned per service manual. Install chain guides and tensioners. Verify all timing marks align correctly. Lock camshafts with holding tools and verify crankshaft timing mark alignment. Install timing chain cover with new gasket and RTV as specified. Torque cover bolts to 19 Nm (14 lb-ft). Remove camshaft holding tools and rotate crankshaft two complete revolutions, verifying timing marks realign correctly.
    ⚠️Incorrect timing chain installation will cause valve-to-piston contact and severe engine damage.
    Torque spec

    Cover Bolts19 Nm (14 lb-ft)
15. 15

    Final Engine Assembly and Installation
    Install valve covers with new gaskets, torque bolts to specification. Install all remaining external components: water pump, thermostat, sensors, accessories. Remove engine from stand and attach to hoist. Carefully lower engine into vehicle, aligning with transmission and engine mounts. Install and torque engine mount bolts to 55 Nm (40 lb-ft) for larger mounts or 31 Nm (23 lb-ft) for smaller mounts per location. Install transmission-to-engine bolts. Reconnect all wiring harnesses, fuel lines, coolant hoses, vacuum lines, and exhaust. Install turbochargers with new gaskets. Install air intake system. Fill engine with 6.0 quarts Motorcraft 0W-20 synthetic oil and new oil filter. Fill cooling system with 13.0 quarts Motorcraft Orange coolant. Reconnect battery.
    Torque spec

    Mounting Bolts31 Nm (23 lb-ft)

Reassembly

1. Double-check all electrical connectors are properly seated and locked
2. Verify all fluid levels are correct: engine oil, coolant, transmission
3. Ensure no tools or rags were left in engine compartment
4. Verify all bolts are tightened to specification, especially critical fasteners
5. Check for any loose hoses or connections
6. Verify timing chain alignment was correct before closing timing cover

Verification

• Prime oil system by cranking engine with fuel pump fuse removed and spark plugs removed until oil pressure builds (typically 10-15 seconds)
• Reinstall spark plugs and fuel pump fuse
• Start engine and monitor oil pressure immediately - should show pressure within 2-3 seconds
• Check for oil, coolant, or fuel leaks while engine runs
• Listen for abnormal noises - ticking, knocking, or rattling indicates problem requiring immediate shutdown
• Allow engine to warm up to operating temperature while monitoring temperature gauge
• Check for proper turbocharger operation and boost pressure
• Verify no warning lights on instrument cluster
• Test drive vehicle and monitor for proper operation, smooth acceleration, and no abnormal noises
• Recheck all fluid levels after test drive
• Monitor oil consumption over first 500 miles - slight increase is normal during ring seating period
• Perform oil and filter change at 500 miles to remove break-in debris

More procedures for this vehicle