This procedure covers the removal and replacement of a single freeze plug (core plug) on the 3.5L EcoBoost V6 engine, requiring partial disassembly to access the affected plug.

Warnings

Tools required

Parts

• Engine freeze plug (cup-type or expansion-type, size specific to location) × 1 — Use OEM specification
• Engine coolant × 1 — Motorcraft Orange Coolant
• Timing cover gasket (if accessing front plugs) × 1 — Use OEM specification
• Accessory mounting gaskets (as needed) × 1 — Use OEM specification

Fluids

• Motorcraft Orange Coolant — 13 qt

Preparation

1. Ensure engine is completely cold to touch
2. Raise vehicle and secure on jack stands rated for vehicle weight
3. Place drain pan beneath engine
4. Remove engine splash shield and underbody panels as needed for access
5. Disconnect negative battery terminal
6. Identify exact location of failed freeze plug to determine required disassembly
7. Take photos of component locations before disassembly for reference during reassembly

Procedure

1. 1

   Drain engine coolant
   Open radiator drain petcock or remove lower radiator hose to drain coolant into appropriate container. Remove radiator cap to allow complete drainage. Dispose of old coolant properly or prepare for reuse if less than 2 years old and clean.
2. 2

   Remove components blocking access
   Depending on freeze plug location, remove necessary components. For front bank plugs, remove accessory drive belt, alternator mounting bolts, and power steering pump mounting bolts (leave hoses attached and secure aside). For rear bank plugs, remove exhaust components and heat shields as needed. Remove any sensors or wiring harnesses blocking access.
   Torque spec

   Mounting Bolts55 Nm (40 lb-ft)

   Sensor Bolts12 Nm (9 lb-ft)
3. 3

   Remove timing cover if necessary
   If accessing front-located freeze plugs behind timing cover, remove timing cover bolts in reverse of tightening sequence (consult service manual for pattern). Carefully pry cover away from engine block using plastic pry tools. Remove and discard old gasket material.
   ⚠Do not damage timing cover sealing surfaces. Use only plastic pry tools on aluminum surfaces.
   Torque spec

   Cover Bolts19 Nm (14 lb-ft)

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

   Clean freeze plug area
   Clean surrounding area of freeze plug thoroughly with wire brush and solvent. Remove all corrosion, old coolant residue, and debris. This ensures proper visibility and prevents contamination during removal.
5. 5

   Remove failed freeze plug
   Using freeze plug removal tool or punch and hammer, carefully drive one edge of freeze plug inward to rotate it in the bore. Once tilted, grip exposed edge with pliers or pry bar and remove plug. Alternatively, drill small hole in center and use slide hammer with screw adapter. Avoid damaging freeze plug bore in engine block.
   ⚠Do not use excessive force that could crack engine block. Work carefully around freeze plug bore.
6. 6

   Inspect and prepare freeze plug bore
   Inspect freeze plug bore in engine block for cracks, corrosion, or damage. Wire brush bore thoroughly to remove all rust and old sealant. Bore must be clean and smooth for new plug to seal properly. Check bore diameter to confirm correct replacement plug size.
7. 7

   Apply sealant to new freeze plug
   Apply thin, even bead of RTV sealant or anaerobic sealant around outer edge of new freeze plug as specified in torque database. Ensure complete coverage but avoid excess that could contaminate cooling system.
   ℹ️Use only coolant-compatible sealant. Some sealants require surface to be completely dry before application.
8. 8

   Install new freeze plug
   Position freeze plug squarely in bore with cup side facing outward (convex side out). Using freeze plug installation tool or appropriately-sized socket and hammer, drive plug evenly into bore until seated flush or slightly below block surface. Ensure plug is not cocked or tilted during installation.
   ⚠Drive plug straight and evenly. A cocked plug will leak and require re-removal.
   Torque spec

   Freeze Plug10 Nm (7 lb-ft)
9. 9

   Reinstall timing cover if removed
   Install new timing cover gasket. Position timing cover onto engine block, ensuring proper alignment of all mounting holes. Install cover bolts and gasket bolts hand-tight, then torque in specified sequence (typically inside-out pattern) to proper specification. Allow gasket sealant to cure if specified by manufacturer.
   Torque spec

   Cover Bolts19 Nm (14 lb-ft)

   Gasket Bolts23 Nm (17 lb-ft)
10. 10

    Reinstall removed components
    Reinstall all components removed for access in reverse order of removal. Install power steering pump, alternator, sensors, exhaust components, and heat shields. Torque all mounting bolts to specification. Reconnect any electrical connectors and ensure proper routing of wiring harnesses.
    Torque spec

    Mounting Bolts55 Nm (40 lb-ft)

    Sensor Bolts12 Nm (9 lb-ft)
11. 11

    Refill cooling system
    Close radiator drain petcock or reinstall lower radiator hose. Fill cooling system with Motorcraft Orange Coolant through radiator and overflow reservoir. Fill to appropriate level (approximately 13 quarts total capacity). Leave radiator cap off for burping process.
12. 12

    Bleed cooling system
    Start engine and allow to reach operating temperature with heater on maximum heat. Monitor coolant level and add as needed while system purges air. Watch for leaks around new freeze plug. Once cooling fans cycle on and off, shut off engine, allow to cool slightly, and top off coolant to proper level. Install radiator cap.
    ⚠️Monitor engine temperature closely during bleeding process. Do not allow engine to overheat.
    ⚠Keep hands clear of cooling fans which may activate at any time.

Reassembly

1. Ensure all mounting bolts are torqued to specification before starting engine
2. Double-check that all electrical connectors are fully seated and locked
3. Verify accessory drive belt is properly routed and tensioned
4. Reinstall engine splash shields and underbody panels
5. Reconnect negative battery terminal

Verification

• Inspect freeze plug installation area for coolant leaks with engine at operating temperature
• Check coolant level in overflow reservoir after engine has cooled - should be at COLD FILL line
• Verify no error codes related to cooling system sensors using scan tool
• Test drive vehicle and monitor temperature gauge for normal operation
• Re-inspect freeze plug area after 24 hours and 100 miles for any delayed seepage
• Check for proper heater operation confirming cooling system is fully bled

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