This procedure covers the removal, inspection, and installation of the main bearings in the 3.5L EcoBoost engine, requiring complete engine removal from the vehicle and disassembly of the lower end.

Warnings

Tools required

Parts

• Main bearing set (standard or oversize) × 1 — Use OEM specification based on crankshaft measurement
• Thrust bearing set × 1 — Use OEM specification
• Main bearing cap bolts (vertical) × 10 — Torque-to-yield - replace if manufacturer specifies
• Main bearing side bolts × 10 — Use OEM specification
• Oil pump gasket or RTV sealant × 1 — Use OEM specification
• Rear main seal × 1 — Use OEM specification
• Oil pan gasket × 1 — Use OEM specification
• Timing cover gasket × 1 — Use OEM specification
• All engine gaskets and seals × 1 — Complete engine gasket set recommended

Fluids

• Motorcraft 5W-20 Synthetic Blend engine oil — 6 qt
• Motorcraft Orange Coolant — 13 qt
• Assembly lube or clean engine oil — 1 qt

Preparation

1. Disconnect negative battery cable and wait 10 minutes for SRS system deactivation
2. Drain engine oil, coolant, and power steering fluid into appropriate containers
3. Remove hood and mark hinge locations for reinstallation alignment
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, fuel lines, coolant hoses, and vacuum lines from engine
7. Remove radiator, cooling fans, and A/C condenser
8. Disconnect exhaust system at manifolds
9. Remove driveshaft and mark for reinstallation
10. Support transmission with transmission jack
11. Remove transmission-to-engine mounting bolts
12. Attach engine hoist with load leveler to engine lift points
13. Remove engine mount bolts and carefully lift engine from vehicle
14. Mount engine securely on engine stand
15. Clean exterior of engine thoroughly before disassembly

Procedure

1. 1

   Remove timing components and front cover
   Remove valve covers, timing chains, guides, tensioners, and timing cover. Remove camshafts if necessary for access. Keep all components organized and labeled for reassembly. Remove crankshaft front seal.
2. 2

   Remove oil pan and oil pump
   Remove oil pan bolts and carefully separate pan from block. Remove oil pump mounting bolts and withdraw oil pump assembly. Inspect oil pump pickup screen for debris.
   ⚠Oil pump alignment is critical. Note orientation and position before removal.
   Torque spec

   Mounting Bolts55 Nm (40 lb-ft)
3. 3

   Remove pistons and connecting rods
   Rotate crankshaft to access each connecting rod. Mark all connecting rods and caps with cylinder number and orientation. Remove connecting rod cap bolts and carefully push piston/rod assemblies out through top of block. Store in numbered order.
   ⚠Use rod bolt protectors or hose sections on rod bolts to prevent crankshaft journal damage during removal.
4. 4

   Identify and mark main bearing caps
   Verify all main bearing caps are numbered 1-5 from front to back. Note the directional arrow or marking on each cap indicating front of engine. Photograph cap positions before removal. The thrust bearing is typically on cap #3.
   ⚠️Main bearing caps MUST be reinstalled in exact original position and orientation. Interchanging caps will destroy the engine.
5. 5

   Remove main bearing cap side bolts
   Working from the outermost caps inward, loosen and remove the side bolts from each main bearing cap. These are horizontal bolts threading into the sides of the caps. Remove bolts gradually in multiple passes to prevent cap binding.
   Torque spec

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

   Remove main bearing cap vertical bolts and caps
   Loosen main bearing cap vertical bolts in 1/4 turn increments, working from the center caps outward. Once all bolts are loose, remove them completely. Carefully lift each cap straight up from the block, keeping caps in order. If caps are stuck, tap gently with soft mallet.
   ⚠Do not pry on machined surfaces. Caps must come off straight to avoid damage.
   Torque spec

   Main Bearing Cap Bolts (Vertical)90 Nm (66 lb-ft)
7. 7

   Remove crankshaft and inspect bearing surfaces
   Carefully lift crankshaft straight up from engine block. Remove upper bearing shells from block and lower shells from caps. Clean all bearing surfaces with lint-free cloth and solvent. Inspect crankshaft journals for scoring, out-of-round, or taper. Measure all journals with micrometer and compare to service specifications.
   ℹ️Crankshaft should be sent to machine shop for magnaflux inspection and precision measurement if any scoring or wear is visible.
8. 8

   Inspect block bearing bores
   Clean all bearing saddles in block and caps thoroughly. Inspect for scoring or damage. Use dial bore gauge to measure bearing bore diameter at multiple points. Check for out-of-round or taper. Verify main bearing bore alignment with precision straightedge.
   ⚠If bearing bores are damaged or out of specification, block must be align-honed by machine shop before reassembly.
9. 9

   Clean and prepare components for assembly
   Clean all bearing saddles, cap mounting surfaces, and bolt holes with brake cleaner. Chase all bolt threads in block with proper tap. Clean crankshaft thoroughly, ensuring oil passages are clear. Blow out all oil passages with compressed air. Wipe all surfaces with clean lint-free cloth and assembly lube.
10. 10

    Install new upper main bearing shells
    Install new upper bearing shells into engine block saddles. Ensure bearing tang engages slot in saddle. Do not use any sealant or adhesive on bearings. Bearing should snap into place and sit flush. Install thrust bearing halves in center main saddle (typically #3) with oil grooves facing out.
    ⚠Never file or scrape bearings. Bearings must be installed dry without sealant.
11. 11

    Install crankshaft and check bearing clearance with Plastigage
    Apply assembly lube to all upper bearing surfaces. Carefully lower crankshaft into block. Place strips of Plastigage across each journal parallel to crankshaft centerline. Install lower bearing shells in caps (without lube for Plastigage check). Install caps in correct position and orientation.
12. 12

    Torque main caps and measure bearing clearance
    Install vertical main cap bolts and torque to specification in sequence from center outward. Install side bolts and torque to specification. Carefully remove caps without rotating crankshaft. Measure flattened Plastigage width and compare to clearance specification (typically 0.0011-0.0018 inches). Record clearances for all journals.
    ⚠Do not rotate crankshaft with Plastigage installed. If clearances are out of specification, verify bearing size and journal diameter before proceeding.
    Torque spec

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

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

    Perform final main bearing installation
    Remove main caps and clean off all Plastigage. Apply assembly lube generously to all bearing surfaces (both upper and lower). Carefully install crankshaft. Apply assembly lube to lower bearing shells in caps. Install main bearing caps in correct order and orientation. Install vertical bolts finger-tight.
14. 14

    Torque main bearing caps to final specification
    Torque main bearing cap vertical bolts to 66 lb-ft in three stages (25%, 50%, then final) working from center cap outward. Install main bearing side bolts and torque to 22 lb-ft. Verify crankshaft rotates freely by hand with smooth even resistance. Check crankshaft endplay with dial indicator (specification typically 0.0051-0.0118 inches).
    ⚠If crankshaft binds or has excessive drag, disassemble immediately and inspect for incorrect bearing installation or debris.
    Torque spec

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

    Main Bearing Side Bolts30 Nm (22 lb-ft)
15. 15

    Install oil pump and oil pan
    Install new rear main seal using proper installation tool. Position oil pump with new gasket, ensuring proper alignment. Install oil pump mounting bolts to specification. Apply RTV sealant to oil pan rail as specified by manufacturer. Install oil pan with new gasket and torque bolts to specification in sequence from center outward.
    ℹ️Follow manufacturer specifications for RTV sealant type and bead size. Excess sealant can block oil passages.
    Torque spec

    Mounting Bolts55 Nm (40 lb-ft)

    Gasket Bolts23 Nm (17 lb-ft)

Reassembly

1. Install connecting rods and pistons in correct cylinder locations with proper orientation
2. Reinstall timing cover, timing chains, guides, tensioners, and camshafts following manufacturer timing procedures
3. Install valve covers with new gaskets
4. Install all remaining external components removed during disassembly
5. Verify crankshaft rotates freely before installing engine in vehicle
6. Install engine in vehicle using hoist and align engine mounts
7. Reconnect transmission and torque mounting bolts to specification
8. Install driveshaft in original orientation using alignment marks
9. Reconnect exhaust system, cooling system, fuel lines, and all electrical connections
10. Install radiator, condenser, and cooling fans
11. Reinstall hood using alignment marks

Verification

• Fill engine with fresh oil and new oil filter to proper level
• Fill cooling system with proper coolant mixture and bleed air from system
• Prime oil system by cranking engine with fuel pump fuse removed until oil pressure gauge shows pressure
• Perform initial start and listen for abnormal noises - engine should run smoothly without knocking
• Monitor oil pressure gauge - should show immediate pressure on startup
• Allow engine to reach operating temperature and check for oil or coolant leaks
• Verify no warning lights on instrument cluster
• Perform test drive and monitor engine operation under various loads
• Recheck oil level after test drive and top off if necessary
• Change oil and filter after 500 miles of break-in period

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