Replace all six spark plugs on the 3.5L EcoBoost V6 engine to maintain proper ignition and engine performance.

Warnings

Tools required

Parts

• Spark plugs (Motorcraft SP-534 or equivalent iridium) × 6 — Motorcraft SP-534

Preparation

1. Ensure engine is completely cold to the touch
2. Park vehicle on level ground and engage parking brake
3. Disconnect negative battery terminal to prevent accidental cranking
4. Verify replacement spark plugs are correct type (iridium, pre-gapped to 0.030" for EcoBoost)

Procedure

1. 1

   Remove engine cover
   Grasp the engine cover firmly and pull upward to disengage the rubber grommets from the mounting posts. The cover is held by friction-fit posts only. Set cover aside.
2. 2

   Access front bank spark plugs (cylinders 1, 2, 3)
   Locate the three ignition coils on the front (radiator side) bank of the engine. They are positioned along the valve cover. Note any harness clips or wiring that may restrict access and carefully move aside without disconnecting.
3. 3

   Remove front bank ignition coils
   Disconnect the electrical connector from each coil by pressing the tab and pulling straight up. Remove the single bolt securing each coil using 8mm socket or T30 Torx bit. Twist coil gently while pulling upward to remove from spark plug well. Inspect coil boot for damage or oil contamination.
   ℹ️If oil is present in spark plug wells, valve cover gaskets may need replacement. Address oil leaks before installing new plugs.
   Torque spec

   Ignition Coil Bolt12 Nm (9 lb-ft)
4. 4

   Clean spark plug wells
   Use compressed air or a vacuum to remove any debris from around the spark plug area before removal. This prevents dirt from falling into the combustion chamber when plug is removed.
5. 5

   Remove front bank spark plugs
   Using the 5/8" spark plug socket with extension, carefully loosen each spark plug 1-2 turns to break it free. Continue unscrewing by hand until plug is fully removed. Inspect old plugs for abnormal wear, fouling, or electrode erosion which may indicate engine issues.
6. 6

   Verify gap and install front bank spark plugs
   Check spark plug gap with gap tool (should be 0.030" for EcoBoost - verify specification on plug box). Apply small amount of anti-seize to threads if desired (optional, not required on modern plugs). Thread each plug by hand into cylinder head until seated, ensuring it threads smoothly without cross-threading. Torque to 15 Nm (11 lb-ft) using torque wrench. Do not overtighten.
   ⚠️Never force a spark plug. If resistance is felt while hand-threading, remove and restart - cross-threading will destroy cylinder head threads.
   Torque spec

   Spark Plug23 Nm (17 lb-ft)
7. 7

   Reinstall front bank ignition coils
   Apply small amount of dielectric grease to inside of coil boot if desired. Align coil over spark plug and press down firmly until fully seated. Install retaining bolt and torque to 12 Nm (9 lb-ft). Reconnect electrical connector until it clicks into place.
   Torque spec

   Ignition Coil Bolt12 Nm (9 lb-ft)
8. 8

   Access rear bank spark plugs (cylinders 4, 5, 6)
   Locate the three ignition coils on the rear (firewall side) bank. Access is more restricted than front bank. You may need to work around brake master cylinder, wiring harnesses, and EVAP components. Use patience and proper extension combinations to reach coil bolts.
   ℹ️Rear bank access is tight. A wobble extension or universal joint may be helpful for reaching coil bolts at certain angles.
9. 9

   Remove rear bank ignition coils
   Disconnect electrical connectors from each rear coil. Remove the single bolt securing each coil using 8mm socket or T30 Torx bit with appropriate extensions. Twist and pull coils upward to remove. Inspect boots for damage.
   Torque spec

   Ignition Coil Bolt12 Nm (9 lb-ft)
10. 10

    Clean rear spark plug wells
    Use compressed air or vacuum to thoroughly clean around each rear spark plug before removal. Debris is more likely to accumulate on the rear bank.
11. 11

    Remove and replace rear bank spark plugs
    Using 5/8" spark plug socket with long extension, carefully remove each rear spark plug. Clean well area again if needed. Verify gap on new plugs (0.030"). Hand-thread new plugs into cylinder head, ensuring smooth threading. Use torque wrench to tighten to 15 Nm (11 lb-ft). Work carefully in the confined space to avoid dropping tools or parts.
    ⚠Use magnetic socket or rubber insert to prevent dropping spark plugs into engine bay. Retrieval from rear bank area is extremely difficult.
    Torque spec

    Spark Plug23 Nm (17 lb-ft)
12. 12

    Reinstall rear bank ignition coils
    Apply dielectric grease to coil boots if desired. Press each coil firmly onto spark plug until fully seated. Install and torque retaining bolts to 12 Nm (9 lb-ft). Reconnect all electrical connectors, ensuring positive engagement.
    Torque spec

    Ignition Coil Bolt12 Nm (9 lb-ft)
13. 13

    Reinstall engine cover and reconnect battery
    Align engine cover with mounting posts and press down firmly until all grommets are seated. Reconnect negative battery terminal.

Reassembly

1. Double-check that all six ignition coil electrical connectors are fully engaged
2. Verify engine cover is properly seated on all mounting posts
3. Ensure no tools or parts were left in engine bay

Verification

• Start engine and listen for smooth idle with no misfires or rough running
• Check for diagnostic trouble codes using OBD-II scanner - no misfire codes should be present
• Perform test drive and verify normal acceleration and power delivery
• Recheck engine bay after test drive for any loose connectors or unusual sounds

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