Freeze Plugs - All

Complete replacement of all engine block freeze plugs on the 3.5L EcoBoost V6, requiring engine removal to access all plugs located on the front, sides, and rear of the block.

Warnings

Tools required

Parts

• Engine freeze plug kit (complete set for 3.5L EcoBoost) × 1 — Use OEM specification - typically 8-10 plugs
• Engine oil and filter × 1 — FL-820S or equivalent
• Engine coolant (pre-mixed) × 2 — Use OEM specification
• Transmission fluid × 1 — Use OEM specification
• Lower radiator hose × 1 — Inspect and replace if damaged
• Upper radiator hose × 1 — Inspect and replace if damaged
• Thermostat housing gasket × 1 — Use OEM specification
• Exhaust manifold gaskets × 2 — Use OEM specification
• Engine mount bolts × 1 — Replace all fasteners

Fluids

• Motorcraft 5W-20 Synthetic Blend — 6 qt
• Motorcraft Orange Coolant — 13 qt
• Motorcraft MERCON LV ATF — 2 qt

Preparation

1. Position vehicle on level surface and engage parking brake
2. Disconnect negative battery cable and secure away from terminal
3. Remove engine cover and beauty shields
4. Drain engine coolant completely into appropriate container
5. Drain engine oil and remove oil filter
6. Remove front skid plate and lower splash shields
7. Relieve fuel system pressure by removing fuel pump fuse and cranking engine until it stalls
8. Take photos of all wiring harness routing, vacuum lines, and hose connections for reference
9. Label all electrical connectors with tape and marker before disconnection

Procedure

1. 1

   Remove hood and front end components
   With assistant, remove hood by marking hinge positions and removing hinge bolts. Remove radiator support cover, grille assembly, and front bumper cover to access radiator and A/C condenser mounting. Disconnect hood latch cable and washer fluid lines.
2. 2

   Disconnect cooling system and A/C
   Remove upper and lower radiator hoses. Disconnect transmission cooler lines from radiator. Recover A/C refrigerant using proper equipment and disconnect A/C lines at condenser. Cap all openings immediately. Remove radiator and condenser assembly as a unit.
   ⚠️A/C system must be professionally recovered. Releasing refrigerant is illegal and dangerous.
3. 3

   Disconnect fuel and electrical systems
   Disconnect fuel supply and return lines at fuel rail using quick-disconnect tool. Disconnect engine wiring harness at firewall connectors (typically 3 main connectors on passenger side). Disconnect throttle body electrical connector, MAF sensor, and all ignition coil connectors. Remove ignition coils.
   ⚠Fuel lines are under residual pressure even after relief procedure. Have rags ready to catch fuel spillage.
4. 4

   Remove intake and exhaust systems
   Remove air intake duct and air filter housing assembly. Unbolt intercooler from brackets and disconnect charge air cooler tubes from turbochargers. Remove exhaust Y-pipe from both turbocharger outlets. Disconnect oxygen sensors and secure wiring away from work area.
5. 5

   Disconnect transmission and transfer case
   Remove transmission bell housing inspection cover. Mark torque converter to flexplate orientation with paint marker. Remove torque converter bolts by rotating engine with socket on crankshaft bolt. Remove transmission-to-engine mounting bolts (note locations as they vary in length). Disconnect transfer case shift motor connector and vent tube.
   ⚠Support transmission with transmission jack before removing all mounting bolts to prevent damage to input shaft.
   Torque spec

   Mounting Bolts55 Nm (40 lb-ft)
6. 6

   Prepare engine for removal
   Disconnect power steering hoses at pump and cap openings. Disconnect heater hoses at firewall. Remove serpentine belt and accessories if they will interfere with removal. Disconnect vacuum lines from brake booster and EVAP system. Remove starter motor.
   Torque spec

   Mounting Bolts55 Nm (40 lb-ft)
7. 7

   Remove engine mounts and extract engine
   Attach engine hoist with chains or straps to factory lifting eyes on engine (one on each cylinder head). Apply slight upward tension. Remove left and right engine mount through-bolts. Slowly raise engine while guiding it forward to clear transmission input shaft. Tilt engine using load leveler as needed to clear firewall and frame rails. Lift engine clear of vehicle and position on engine stand.
   ⚠️Have assistant guide engine during removal. Watch for snagged hoses, wires, or interference with body/frame. Move slowly and check clearances constantly.
   Torque spec

   Mounting Bolts55 Nm (40 lb-ft)
8. 8

   Locate and document freeze plug positions
   With engine on stand, clean exterior block surfaces around freeze plug locations. Identify all freeze plug locations: typically 2 on front of block, 3-4 on each side near cylinder heads, and 2-3 on rear bell housing surface. Note sizes and positions. Typical 3.5L EcoBoost has 8-10 freeze plugs total.
9. 9

   Remove old freeze plugs
   Using freeze plug removal tool or center punch and hammer, carefully knock one edge of freeze plug inward to tilt it in bore. Do not strike plug directly into block. Use locking pliers or pry bar to extract tilted plug. Alternatively, drill small hole in center of plug and use slide hammer with screw adapter. Repeat for all freeze plugs. Inspect bores for corrosion or damage.
   ⚠Do not use excessive force or pry against aluminum block casting. Damaged freeze plug bore will require block replacement or professional machining repair.
10. 10

    Prepare bores and install new freeze plugs
    Clean each freeze plug bore thoroughly with wire brush and solvent. Remove all corrosion, old sealant, and debris. Dry bores completely. Apply thin bead of high-temperature anaerobic sealant around outer edge of new freeze plug (cup side out). Position plug squarely in bore using freeze plug installation tool. Drive plug in evenly using large socket or installation tool until flush with block surface or approximately 1-2mm below surface (depending on plug design). Torque threaded freeze plugs per specification.
    ℹ️Some freeze plugs are press-fit (cup style) and others are threaded. Use appropriate installation method for each type.
    Torque spec

    Freeze Plug10 Nm (7 lb-ft)
11. 11

    Inspect and clean mating surfaces
    With all freeze plugs installed, clean all gasket surfaces on engine block, cylinder heads, exhaust manifolds, and transmission bell housing. Scrape away old gasket material with plastic scraper. Clean surfaces with brake cleaner and lint-free cloth. Inspect for damage or warping. Replace gaskets that were disturbed during removal.
12. 12

    Reinstall engine in vehicle
    Reverse removal procedure. Position engine on hoist and carefully lower into engine bay. Align engine with transmission and guide input shaft into torque converter pilot. Install engine mount bolts finger-tight initially. Align all mounts and torque to specification. Reconnect transmission to engine with mounting bolts.
    ⚠Ensure torque converter is fully seated in transmission pump before mating engine. Verify 3 distinct clicks when installing converter and check that converter hub is recessed approximately 1/2 inch from bell housing face.
    Torque spec

    Mounting Bolts55 Nm (40 lb-ft)
13. 13

    Reconnect all systems
    Reinstall starter motor. Reconnect all electrical connectors per photos taken during disassembly. Connect fuel lines, heater hoses, power steering hoses, and vacuum lines. Install exhaust system and torque fasteners to specification. Reinstall intercooler piping and air intake system. Install serpentine belt and accessories.
    Torque spec

    Gasket Bolts23 Nm (17 lb-ft)

    Sensor Bolts12 Nm (9 lb-ft)
14. 14

    Reinstall cooling system and A/C
    Install radiator and condenser assembly. Connect transmission cooler lines. Install upper and lower radiator hoses with new clamps. Reconnect A/C lines with new O-rings and proper lubricant. Reinstall front bumper, grille, and radiator support components. Reinstall hood, aligning to marked positions.
    Torque spec

    Cover Bolts19 Nm (14 lb-ft)
15. 15

    Refill fluids and bleed cooling system
    Install new oil filter and refill engine with 6 quarts of 5W-20 oil. Fill cooling system using refill funnel with vacuum fill tool if available, or by conventional fill and bleed method. Open bleeder screw on thermostat housing and fill until coolant flows from bleeder without bubbles. Top off transmission fluid as needed. Check all other fluid levels including power steering and brake fluid.

Reassembly

1. Verify all electrical connectors are fully seated and locked
2. Check that all vacuum lines and hoses are connected per reference photos
3. Ensure all ground straps are reinstalled to original locations
4. Verify serpentine belt is properly routed on all pulleys
5. Double-check that no tools or rags were left in engine bay

Verification

• Reconnect battery and turn ignition to ON position without starting. Check for fuel leaks at all connection points
• Start engine and immediately check for oil pressure on instrument cluster. Engine should start within 5 seconds
• Check for coolant, oil, fuel, or transmission fluid leaks while engine idles
• Monitor coolant temperature and verify cooling fans operate at normal temperature (approximately 200°F)
• After reaching operating temperature, check coolant level and add if necessary. Recheck for leaks
• Test drive vehicle to verify normal operation. Check transmission shifts properly and engine develops full power
• Recheck all fluid levels after test drive with engine at operating temperature
• Have A/C system evacuated and recharged by qualified technician
• Perform final inspection of all connections and torque specifications after 50-100 miles of driving

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