Replace main bearings on the 3.5L EcoBoost V6 engine, requiring complete engine removal, disassembly, crankshaft inspection, and precision reassembly with proper clearance verification.

Warnings

Tools required

Parts

• Main bearing set (standard or appropriate undersize) × 1 — Use OEM Ford specification
• Thrust bearing set × 1 — Use OEM Ford specification
• Oil pan gasket × 1 — Use OEM specification
• Front cover gasket × 1 — Use OEM specification
• Rear main seal × 1 — Use OEM specification
• Valve cover gaskets × 2 — Use OEM specification
• Timing chain components (inspect and replace as needed) × 1 — Use OEM specification
• Main bearing cap bolts (if torque-to-yield) × 1 — Use OEM specification
• Oil filter × 1 — FL-500S or equivalent
• Engine oil × 1 — Motorcraft 0W-20
• Engine coolant × 1 — Motorcraft Orange
• RTV silicone sealant (Motorcraft TA-31) × 1 — TA-31
• Engine assembly lube × 1 — Use OEM specification

Fluids

• Motorcraft 0W-20 Full Synthetic — 6 qt
• Motorcraft Orange Coolant — 13 qt

Preparation

1. Position vehicle on level ground with wheels chocked and parking brake engaged
2. Disconnect negative battery cable and isolate from terminal
3. Drain engine oil and coolant completely into appropriate containers
4. Remove engine cover and air intake assembly
5. Relieve fuel system pressure by removing fuel pump fuse and cranking engine until it stalls
6. Disconnect all electrical connectors, labeling each for reinstallation
7. Remove radiator, intercooler, and cooling system hoses
8. Disconnect exhaust system at manifolds
9. Remove driveshaft (RWD configuration)
10. Support transmission with transmission jack
11. Remove transmission-to-engine mounting bolts
12. Disconnect power steering lines if equipped (verify electric system on this model)
13. Disconnect A/C compressor and secure aside without disconnecting refrigerant lines
14. Attach engine hoist with proper sling positioning on factory lift points
15. Remove engine mount bolts and carefully extract engine from vehicle
16. Mount engine securely on engine stand, ensuring stand is rated for engine weight

Procedure

1. 1

   Remove external engine components
   With engine on stand, remove alternator, A/C compressor bracket, power steering pump (if applicable), starter, and all remaining accessories. Remove turbochargers and exhaust manifolds. Remove fuel rails and injectors, protecting injector tips. Remove intake manifolds (upper and lower). Remove valve covers, noting bolt locations as they may be different lengths.
2. 2

   Remove timing components
   Lock crankshaft using holding tool. Remove harmonic balancer using puller. Remove front timing cover after removing all mounting bolts. Align timing marks and photograph timing chain position for reference. Remove timing chains, guides, and tensioners. Inspect all timing components for wear; replace if excessive slack or damage is present.
   Torque spec

   Cover Bolts19 Nm (14 lb-ft)

   Mounting Bolts54 Nm (40 lb-ft)
3. 3

   Remove oil pan and oil pump
   Remove oil pan bolts in reverse torque sequence (work from ends toward center). Carefully separate oil pan from block. Remove oil pump pickup tube. Remove oil pump assembly by extracting mounting bolts. Inspect oil pump for wear and debris.
   Torque spec

   Gasket Bolts23 Nm (17 lb-ft)

   Mounting Bolts54 Nm (40 lb-ft)
4. 4

   Remove pistons and connecting rods
   Rotate engine so crankshaft journals are accessible. Mark each connecting rod cap and rod with cylinder number and orientation using permanent marker or stamps. Remove connecting rod cap bolts. Push each piston/rod assembly up and out of cylinder bore, protecting crankshaft journals with rubber hose over rod bolts. Store assemblies in order.
5. 5

   Mark and remove main bearing caps
   Carefully mark each main bearing cap with its position number (1-4 from front) and orientation arrow pointing toward front of engine. Note that caps are NOT interchangeable. Remove main bearing side bolts first, then vertical main bearing cap bolts in sequence from outer caps toward center. Carefully lift caps straight up and store in order with bearings in place for inspection.
   ⚠Main bearing caps must be marked before removal. Installing caps in wrong position or orientation will destroy the engine.
   Torque spec

   Main Bearing Cap Bolts (Vertical)90 Nm (66 lb-ft)

   Main Bearing Side Bolts30 Nm (22 lb-ft)
6. 6

   Remove crankshaft and inspect
   Carefully lift crankshaft straight up from engine block. Inspect crankshaft journals with micrometer for out-of-round (maximum 0.0002 inch), taper, and scoring. Measure all main journal diameters. Standard diameter is approximately 2.0861-2.0868 inches; verify with Ford specifications. Any journal out of specification requires crankshaft grinding or replacement. Remove upper main bearings from block and inspect for wear patterns, scoring, or embedded debris.
   ⚠Crankshaft journals must be within 0.0002 inch tolerance for roundness. Excessive wear requires machining or replacement.
7. 7

   Inspect engine block bearing bores
   Clean all main bearing saddles thoroughly with solvent and lint-free cloth. Use dial bore gauge or inside micrometer to measure each main bearing bore for out-of-round and taper. Inspect block for cracks, especially around main bearing webs. Verify oil passage holes are clear by spraying with brake cleaner. Any bore damage may require align-honing or block replacement.
8. 8

   Clean all components
   Thoroughly clean crankshaft, main bearing caps, and engine block surfaces with solvent. Clean all oil passages in crankshaft using bore brushes and compressed air (blow in opposite direction of oil flow). Ensure bearing saddles in block and caps are spotlessly clean and free of old bearing material. Clean and inspect main bearing cap bolts; replace if torque-to-yield type (verify with Ford specifications). Chase all bolt threads in block with appropriate thread chaser.
   ℹ️Any contamination in bearing surfaces will cause immediate failure upon startup. Cleanliness is absolutely critical.
9. 9

   Install new upper main bearings
   Select correct bearing size based on crankshaft measurements (standard or undersize). Install upper main bearings (with oil holes) into engine block saddles, ensuring bearing tangs seat firmly in block notches. Do NOT use any adhesive or assembly lube on bearing backs; they must seat metal-to-metal. Lightly coat bearing surfaces with clean engine oil or assembly lube. Verify oil passages align correctly.
10. 10

    Install crankshaft and check clearances
    Carefully lower crankshaft into position in block. Install thrust bearing halves on center main bearing (position 3, verify with specifications). Place Plastigage strips across each main journal parallel to crankshaft centerline. Install lower bearings in caps (without oil holes). Carefully install main bearing caps in correct positions with orientation marks toward front. Install and torque main bearing cap vertical bolts to specification, then side bolts. DO NOT rotate crankshaft.
    ⚠Do not rotate crankshaft with Plastigage installed. This will give false readings and may damage bearings.
    Torque spec

    Main Bearing Cap Bolts (Vertical)90 Nm (66 lb-ft)

    Main Bearing Side Bolts30 Nm (22 lb-ft)
11. 11

    Measure bearing clearances
    Remove main bearing caps (vertical bolts first, then side bolts) without rotating crankshaft. Measure flattened Plastigage at widest point using scale on package. Acceptable clearance is typically 0.0009-0.0019 inches for EcoBoost engines; verify exact specification with Ford service data. If clearance is too tight or too loose, verify correct bearing size and crankshaft journal dimensions. Remove all Plastigage material completely before final assembly.
    ⚠Bearing clearance must be within specification. Too tight causes seizure; too loose causes bearing failure and oil pressure loss.
12. 12

    Final main bearing installation
    Remove all Plastigage residue with clean cloth. Apply thin coat of engine assembly lube to all bearing surfaces. Install crankshaft and main bearing caps in correct order and orientation. Install NEW main bearing cap bolts if torque-to-yield type. Hand-start all vertical bolts first, then side bolts. Torque vertical main bearing cap bolts to 90 Nm (66 lb-ft) in sequence from center outward. If TTY bolts, follow with additional angle rotation per Ford specification. Torque side bolts to 30 Nm (22 lb-ft). Verify crankshaft rotates freely by hand with no binding.
    ⚠Torque sequence is critical. Always torque from center main bearing outward to properly align components.
    Torque spec

    Main Bearing Cap Bolts (Vertical)90 Nm (66 lb-ft)

    Main Bearing Side Bolts30 Nm (22 lb-ft)
13. 13

    Check crankshaft endplay
    Using feeler gauge or dial indicator, measure crankshaft endplay (thrust clearance) at center main bearing. Push crankshaft fully forward, zero indicator, then pull fully rearward and note reading. Typical specification is 0.0035-0.0106 inches; verify exact specification. Excessive endplay indicates incorrect thrust bearing installation or worn thrust surfaces.
14. 14

    Reinstall connecting rods and pistons
    Install connecting rod bearings and coat with assembly lube. Protect crankshaft journals with rubber hose over rod bolts. Install each piston/rod assembly into correct cylinder with orientation marks correct. Install rod caps in proper orientation and torque to specification per Ford service manual (not provided in torque list). Verify each rod has proper side clearance and rotates freely on journal.
15. 15

    Reinstall oil pump and oil pan
    Install new rear main seal in housing. Install oil pump with new gasket, torque mounting bolts to specification. Install oil pump pickup tube. Clean oil pan and block mating surfaces completely. Apply thin bead of RTV sealant at front cover-to-block joints. Install new oil pan gasket and position oil pan. Install and torque oil pan bolts in sequence from center outward.
    Torque spec

    Gasket Bolts23 Nm (17 lb-ft)

    Mounting Bolts54 Nm (40 lb-ft)
16. 16

    Reinstall timing components
    Install timing chains, guides, and tensioners per factory timing marks and procedures. Install front timing cover with new gasket, applying RTV at block-to-pan joints. Torque cover bolts to specification. Install harmonic balancer using proper installation tool (never hammer onto crankshaft). Torque balancer bolt to specification.
    Torque spec

    Cover Bolts19 Nm (14 lb-ft)

    Mounting Bolts54 Nm (40 lb-ft)
17. 17

    Complete engine assembly
    Install valve covers with new gaskets. Install intake manifolds with new gaskets. Install fuel rails and injectors. Install turbochargers and exhaust manifolds with new gaskets. Reinstall all accessories, sensors, and electrical connectors. Double-check all fasteners for proper torque and all connections for security.
    Torque spec

    Sensor Bolts12 Nm (9 lb-ft)

    Electrical Connector Bolts8 Nm (6 lb-ft)

Reassembly

1. Reverse engine removal procedure to install engine back into vehicle
2. Reconnect transmission and torque all mounting bolts to specification
3. Install engine mounts and torque to specification
4. Reconnect exhaust system, driveshaft, and all coolant hoses
5. Reconnect all electrical connectors, fuel lines, and vacuum lines
6. Install radiator and intercooler with fresh coolant
7. Refill engine with correct grade and quantity of fresh oil (6 quarts 0W-20)
8. Install new oil filter and verify drain plug is tight
9. Double-check all fluid levels before starting engine
10. Reconnect battery negative cable

Verification

• With ignition off, verify engine rotates freely by hand at crankshaft pulley
• Prime oil system by cranking engine with fuel pump fuse removed until oil pressure registers
• Reinstall fuel pump fuse and start engine, monitoring oil pressure immediately
• Oil pressure should register within 2-3 seconds; shut down immediately if no pressure
• Allow engine to idle and verify no unusual noises, knocking, or rattling
• Monitor for any oil or coolant leaks from oil pan, timing cover, or valve covers
• Bring engine to operating temperature and verify proper coolant circulation
• After initial warm-up and cool-down, recheck oil level and inspect for leaks
• Perform test drive and monitor for proper operation, oil pressure, and temperature
• After 500 miles, change oil and filter, inspect for metal debris in oil
• Recommended to retorque cylinder head bolts if accessible after initial heat cycle per Ford procedures

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