Freeze Plugs - All

Complete replacement of all freeze plugs (core plugs/expansion plugs) on the 3.5L EcoBoost V6 engine, requiring engine removal or significant component disassembly to access all plugs on both cylinder banks.

Warnings

Tools required

Parts

• Engine freeze plug set (front, rear, and side plugs) × 1 — Use OEM specification
• Engine oil and filter × 1 — Use OEM specification
• Coolant × 2 — Motorcraft Orange
• Transmission mount bolts × 1 — Use OEM specification
• Engine mount hardware (if damaged) × 1 — Use OEM specification
• Intake manifold gaskets × 1 — Use OEM specification
• Valve cover gaskets × 2 — Use OEM specification
• Exhaust manifold gaskets × 2 — Use OEM specification
• Various engine cover and sensor gaskets × 1 — Use OEM specification

Fluids

• Motorcraft Orange Coolant — 13 qt
• Motorcraft 0W-20 Full Synthetic — 6 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 approved recycling container
4. Drain engine oil and remove oil filter
5. Remove engine cover and intake air system
6. Remove both intercoolers and charge air cooler piping
7. Document all electrical connections with photos before disconnecting
8. Relieve fuel system pressure by removing fuel pump fuse and cranking engine until it stalls
9. Place fender covers to protect paint during engine work

Procedure

1. 1

   Remove upper engine components
   Remove both valve covers, intake manifold, and throttle body assembly. Disconnect all vacuum lines, fuel lines, and electrical connectors from intake manifold and fuel rails. Remove ignition coils and set aside. Disconnect PCV system hoses. This provides access to some side freeze plugs and prepares for engine tilting.
2. 2

   Disconnect exhaust system
   Remove both turbochargers following manufacturer procedure (disconnect oil feed and return lines, coolant lines, and exhaust connections). Remove exhaust manifolds from both cylinder banks. Cap all open oil and coolant ports to prevent contamination.
3. 3

   Disconnect engine accessories and front components
   Remove serpentine belt, alternator, A/C compressor (set aside without disconnecting refrigerant lines), power steering pump bracket if equipped. Remove radiator and cooling fan assembly. Disconnect upper and lower radiator hoses, heater hoses, and all coolant lines.
4. 4

   Support and disconnect engine mounts
   Install engine support fixture or attach engine hoist to factory lifting points. Support transmission with transmission jack. Remove engine mount bolts on both sides. Disconnect transmission-to-engine bolts but do not separate transmission fully (unless removing engine completely).
   ⚠️Ensure engine hoist is properly rated and securely attached before removing mount bolts. Verify transmission is adequately supported.
   Torque spec

   Mounting Bolts55 Nm (40 lb-ft)
5. 5

   Tilt or raise engine for access
   Carefully raise and tilt engine forward to gain access to rear freeze plugs. For complete access to all plugs, engine removal may be necessary. Ensure all hoses, wires, and lines are disconnected before tilting more than 6 inches. Check clearance around firewall and brake master cylinder.
6. 6

   Locate all freeze plugs
   On the 3.5L EcoBoost, identify all freeze plug locations: typically 2-3 plugs on each side of the block (driver and passenger), 2-4 rear plugs between engine and transmission bellhousing, and 1-2 front plugs behind timing cover area. Clean area around each plug to identify exact positions.
7. 7

   Remove front freeze plugs
   For front freeze plugs accessible with engine tilted, use freeze plug removal tool or carefully drive a drift punch at an angle into the edge of the plug to rotate and pry it out. Alternatively, drill a small hole in center and use slide hammer. Clean the bore thoroughly with wire brush, removing all old sealant and corrosion.
8. 8

   Remove side freeze plugs
   Access side freeze plugs on both cylinder banks. These may require removal of engine mount brackets or other obstructions. Use same removal technique as front plugs. Inspect bores carefully for corrosion or pitting that may prevent proper seal.
9. 9

   Remove rear freeze plugs
   Access rear freeze plugs between engine and bellhousing. This is the most difficult access point and may require complete engine removal or transmission lowering depending on specific plug locations. Remove each plug carefully to avoid damaging the bore.
   ⚠Rear plugs have extremely limited access. Work slowly to avoid slipping and damaging surrounding components or your hands.
10. 10

    Prepare freeze plug bores
    Thoroughly clean each freeze plug bore with wire brush and brake cleaner. Remove all rust, scale, old sealant, and debris. Inspect each bore for damage, cracks, or excessive corrosion. Bores must be smooth and clean for proper plug seating. Use fine sandpaper if needed to smooth minor imperfections.
11. 11

    Install new freeze plugs
    Apply RTV sealant or thread sealant (as specified) around outer edge of each new freeze plug. Using appropriate size freeze plug installation tool, drive each plug squarely into its bore until seated flush or slightly below the block surface (typically 1-2mm below). Ensure plug does not cock to one side during installation. For threaded freeze plugs (if equipped), apply thread sealant and torque to specification.
    ⚠Plugs must be installed perfectly square. Cocked plugs will leak. Use proper installation tool, not a hammer and socket.
    Torque spec

    Freeze Plug10 Nm (7 lb-ft)
12. 12

    Inspect and allow sealant to cure
    Visually inspect each installed freeze plug to ensure it is properly seated and flush. Verify sealant is visible around edges. Allow sealant to cure per manufacturer specifications (typically 1 hour minimum) before reinstalling engine or adding coolant.
13. 13

    Reinstall engine to original position
    Carefully lower engine back to original position using hoist. Align engine mounts and install mounting bolts to specification. Reconnect transmission-to-engine bolts. Remove engine hoist and support fixture only after all mounts are secured.
    Torque spec

    Mounting Bolts55 Nm (40 lb-ft)
14. 14

    Reinstall exhaust and turbocharger components
    Install new exhaust manifold gaskets and reinstall exhaust manifolds. Reinstall both turbochargers with new gaskets, reconnecting all oil feed/return lines and coolant lines. Ensure all fasteners are torqued to specification.
    Torque spec

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

    Reinstall intake and valve covers
    Install new intake manifold gaskets and reinstall intake manifold, throttle body, and fuel rail assemblies. Install new valve cover gaskets and reinstall both valve covers. Reconnect all vacuum lines, fuel lines, PCV hoses, and electrical connectors per photos taken during disassembly. Reinstall ignition coils.
    Torque spec

    Gasket Bolts23 Nm (17 lb-ft)

    Cover Bolts19 Nm (14 lb-ft)
16. 16

    Reinstall cooling system and accessories
    Reinstall radiator and cooling fan assembly. Reconnect all coolant hoses. Reinstall A/C compressor, alternator, power steering pump bracket, and serpentine belt. Reinstall intercoolers and charge air cooler piping. Install new engine oil filter.
17. 17

    Reinstall sensors and final components
    Reconnect all remaining electrical connectors, ensuring proper routing and securing clips. Reinstall intake air system and engine cover. Reconnect battery negative cable.
    Torque spec

    Sensor Bolts12 Nm (9 lb-ft)
18. 18

    Fill fluids and bleed cooling system
    Fill engine with 6 quarts of Motorcraft 0W-20 synthetic oil. Fill cooling system with Motorcraft Orange coolant following proper bleeding procedure: fill radiator, start engine with heater on maximum, add coolant as level drops, run until thermostat opens and cooling fans cycle. Check for leaks around all freeze plugs while engine warms up.
    ⚠Monitor coolant level closely during initial warm-up. Air pockets can cause overheating and engine damage.

Reassembly

1. Double-check that all electrical connectors are fully seated and locked
2. Verify all hose clamps are tight and hoses are properly routed
3. Ensure serpentine belt is properly seated on all pulleys
4. Confirm all intake and vacuum connections are secure with no leaks
5. Verify oil drain plug and filter are properly installed before adding oil

Verification

• Start engine and immediately check for coolant leaks around all freeze plug locations
• Allow engine to reach full operating temperature while monitoring coolant level
• Check for oil leaks around valve covers and other disturbed gaskets
• Verify engine runs smoothly with no misfires or unusual noises
• Recheck coolant level after engine cools and top off if needed
• Test drive vehicle and monitor temperature gauge for proper operation
• Recheck all freeze plug areas after 100 miles of driving for any seepage
• Check engine oil level after test drive and adjust if necessary

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