This procedure covers the replacement of a single freeze plug (core plug) on the 2021-2024 Ford F-150 3.5L EcoBoost engine, requiring partial disassembly to access the failed plug.

Warnings

Tools required

Parts

• Engine freeze plug (core plug) × 1 — Use OEM specification - size depends on location
• Engine block sealant × 1 — Permatex Form-A-Gasket or equivalent
• Engine coolant × 1 — Motorcraft Orange Coolant

Fluids

• Motorcraft Orange Coolant — 13 qt

Preparation

1. Park vehicle on level ground and allow engine to cool completely for at least 2 hours
2. Disconnect negative battery terminal and secure away from battery post
3. Raise vehicle with floor jack and support securely on jack stands rated for vehicle weight
4. Remove engine belly pan/skid plate if equipped
5. Place large drain pan beneath radiator drain cock
6. Identify exact freeze plug location and determine required component removal for access
7. Take photos of component locations and electrical connector orientations before removal

Procedure

1. 1

   Drain engine coolant
   Open radiator drain cock (petcock) located at bottom passenger side of radiator. Allow coolant to drain completely into drain pan. If freeze plug location is low on block, may need to drain completely. For higher plugs, partial drain may be acceptable. Remove radiator cap to speed draining.
2. 2

   Remove access components
   Based on freeze plug location, remove necessary components for access. Common obstructions include: starter motor (disconnect electrical connectors, remove mounting bolts), exhaust components (disconnect sensors, remove mounting bolts), wiring harnesses (unbolt mounting brackets, move aside), and coolant hoses. Label all electrical connectors and hardware for reinstallation.
   ⚠Support any components being removed with appropriate stands or wire. Do not let components hang by wiring or hoses.
   Torque spec

   Mounting Bolts55 Nm (40 lb-ft)

   Electrical Connector Bolts8 Nm (6 lb-ft)
3. 3

   Clean freeze plug area
   Clean around the failed freeze plug thoroughly with wire brush to remove dirt, rust, and debris. This prevents contamination from falling into coolant passages when plug is removed. Wipe area clean with rags.
4. 4

   Remove failed freeze plug
   Using freeze plug removal tool or large flathead screwdriver, carefully pry one edge of the freeze plug to create a starting point. Work around the perimeter to break the seal. Once loosened, use pliers or the removal tool to extract the plug completely from the block. Inspect the bore carefully for cracks, corrosion, or damage. If bore is damaged, engine block repair may be required.
   ⚠Do not use excessive force that could damage the freeze plug bore in the engine block. A damaged bore will prevent proper sealing of the new plug.
5. 5

   Prepare freeze plug bore
   Thoroughly clean the freeze plug bore in the engine block using a wire brush or emery cloth. Remove all old sealant, rust, and corrosion. The bore must be clean and smooth for the new plug to seal properly. Wipe clean with a lint-free rag. Ensure bore is completely dry before installation.
6. 6

   Prepare new freeze plug
   Apply engine block sealant around the outer edge of the new freeze plug as specified in torque specifications. Ensure even coverage but avoid excessive sealant that could squeeze into coolant passages. Verify new plug is the correct size and type for the location.
7. 7

   Install new freeze plug
   Position the new freeze plug in the bore, ensuring it is centered and seated square to the block. Using a freeze plug installation tool or appropriately-sized socket and extension, carefully drive the plug into the bore. The plug should seat evenly and be flush or slightly recessed from the block surface. If torque specification applies (expandable type plug), tighten to specification using appropriate tool.
   ⚠Install plug evenly to prevent cocking or distortion. A cocked plug will leak. Tap progressively around the perimeter if using manual installation method.
   Torque spec

   Freeze Plug10 Nm (7 lb-ft)
8. 8

   Verify freeze plug installation
   Inspect the installed freeze plug to ensure it is seated evenly around the entire circumference. The plug should be flush with or slightly below the block surface. Check for any gaps or high spots that could indicate improper installation. Allow sealant to set per manufacturer instructions (typically 15-30 minutes) before adding coolant.
9. 9

   Reinstall removed components
   Reinstall all components removed for access in reverse order of removal. Install any gaskets or seals as required. Clean gasket mating surfaces thoroughly before installing new gaskets. Reconnect all electrical connectors to their original locations using reference photos. Torque all fasteners to specification.
   ℹ️Clean mating surfaces thoroughly as specified for gasket surface bolts.
   Torque spec

   Mounting Bolts55 Nm (40 lb-ft)

   Electrical Connector Bolts8 Nm (6 lb-ft)

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

    Refill cooling system
    Close radiator drain cock securely. Fill cooling system with Motorcraft Orange Coolant through radiator fill neck and coolant reservoir to proper level. Use 50/50 mix of coolant and distilled water or pre-mixed coolant. Fill slowly to minimize air pockets. Refer to capacity of 13 quarts total system capacity.
11. 11

    Bleed cooling system
    With radiator cap off, start engine and allow to warm to operating temperature. Monitor coolant level and add as needed while engine warms. Run heater on high to circulate coolant through heater core. Watch for air bubbles in radiator. When thermostat opens (coolant begins circulating rapidly), top off coolant. Once no air bubbles appear and coolant level stabilizes, install radiator cap.
    ⚠Monitor closely for leaks at new freeze plug during warm-up. Shut down immediately if leak is observed.
12. 12

    Check for leaks and final inspection
    With engine at operating temperature, inspect freeze plug installation area carefully for any coolant leaks. Check all reinstalled components, gaskets, and connections. Allow engine to run for 10-15 minutes, then shut off and let cool slightly. Recheck coolant level in reservoir and add if needed. Reinstall belly pan/skid plate. Reconnect negative battery terminal.

Reassembly

1. Ensure all electrical connectors are fully seated and locked in place
2. Verify all mounting bolts and sensors are torqued to specification
3. Double-check coolant level in reservoir after cooling system reaches operating temperature
4. Dispose of old coolant properly at approved recycling facility

Verification

• Start engine and verify no coolant leaks from freeze plug area after reaching operating temperature
• Check coolant level in reservoir is between MIN and MAX marks when engine is cold
• Verify no warning lights on instrument cluster related to cooling system
• Monitor coolant level and temperature gauge during first 100 miles of driving for any abnormalities
• Inspect freeze plug area from underneath vehicle after first drive cycle to confirm no leaks

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