Tune-Up - Minor

Replace spark plugs and engine air filter to restore optimal engine performance and fuel efficiency on the 3.5L EcoBoost V6 engine.

Warnings

Tools required

Parts

• Spark plugs (6) × 6 — Motorcraft SP-537 or equivalent iridium
• Engine air filter × 1 — Motorcraft FA-1927

Preparation

1. Ensure engine is completely cold to the touch
2. Park vehicle on level ground and engage parking brake
3. Open hood and secure with prop rod
4. Disconnect negative battery cable to prevent accidental ignition system activation
5. Remove engine cover by pulling upward on integrated pull tabs (no tools required)
6. Gather all replacement parts and verify correct specifications

Procedure

1. 1

   Remove engine air filter
   Locate the air filter housing on the driver's side of the engine bay. Release the metal clips securing the air box lid (typically 4-6 clips depending on production date). Carefully lift the lid and remove the old air filter element. Inspect the housing for debris, leaves, or moisture and clean with compressed air or vacuum if needed.
2. 2

   Install new engine air filter
   Position the new air filter element into the housing, ensuring the rubber gasket seats properly around the perimeter. The filter is directional - verify airflow arrow points toward the engine if marked. Lower the air box lid and secure all clips firmly until they click into place.
   Torque spec

   Air Box Clips5 Nm (4 lb-ft)
3. 3

   Access ignition coils
   With the engine cover removed, locate all six ignition coil-on-plug assemblies. They are positioned directly above each spark plug on both cylinder banks. The passenger side bank is more accessible; the driver's side requires reaching behind and around the turbocharger assemblies. Note the position of each coil for proper reassembly.
4. 4

   Disconnect ignition coil electrical connectors
   Starting with the passenger side bank (cylinders 1, 2, 3), press the release tab on each coil electrical connector and pull straight up to disconnect. The connectors may be tight due to weather sealing. For the driver's side bank (cylinders 4, 5, 6), reach carefully around the turbocharger intake plumbing. Do not pull on wires, only the connector body.
   ⚠Turbocharger components may have sharp edges. Use care when reaching around intake and exhaust plumbing.
5. 5

   Remove ignition coils
   Each coil is held by a single 8mm bolt. Remove the bolt from each coil using a ratchet with extension. Grasp the coil body firmly and pull straight up with a twisting motion to break the seal. The coils may be tight in the valve cover boots. For driver's side coils, a longer extension or swivel socket may be necessary due to limited clearance around the turbos.
   ℹ️If coil boots remain stuck in valve cover, use needle-nose pliers to carefully extract them before proceeding.
6. 6

   Clean spark plug wells
   Before removing spark plugs, use compressed air or a vacuum to thoroughly clean around each spark plug well. This prevents dirt, debris, or carbon deposits from falling into the cylinders when plugs are removed. Pay special attention to the driver's side where debris accumulates more readily.
   ⚠Any debris that enters the cylinder can cause severe engine damage. Ensure wells are completely clean before removing plugs.
7. 7

   Remove old spark plugs
   Using a 5/8-inch spark plug socket with appropriate extensions, carefully loosen each spark plug 1/4 turn initially to break it free. Then unthread completely by hand, keeping the socket straight to avoid cross-threading. Remove all six plugs and inspect electrodes for wear patterns, oil fouling, or abnormal deposits that may indicate engine issues.
8. 8

   Prepare and gap new spark plugs
   Remove new spark plugs from packaging and verify they match the correct specification (typically 0.035-inch gap for EcoBoost). Check gap with a feeler gauge even though plugs come pre-gapped. Apply a small amount of anti-seize compound to the threads only - avoid getting any on the electrode or insulator. Do not apply anti-seize to more than 2/3 of the thread length.
   ⚠Never use anti-seize on the electrode end or insulator. Contamination can cause misfires and fouling.
9. 9

   Install new spark plugs
   Thread each new spark plug by hand into its cylinder, turning clockwise until finger-tight. This ensures proper threading and prevents cross-threading damage. Once seated by hand, use the torque wrench and spark plug socket to tighten to 15 Nm (11 lb-ft). The EcoBoost uses aluminum heads, so precise torque is critical - do not over-tighten. Install all six plugs following this procedure.
   ⚠️Over-torquing spark plugs in aluminum heads can strip threads, requiring expensive cylinder head repair or replacement.
10. 10

    Reinstall ignition coils
    Apply a thin coating of dielectric grease to the inside of each coil boot where it contacts the spark plug insulator. Push each coil firmly into place until it seats completely on the spark plug and valve cover. Install the 8mm mounting bolt for each coil and tighten to 12 Nm (9 lb-ft) using the torque wrench.
    Torque spec

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

    Reconnect electrical connectors
    Reconnect the electrical connector to each ignition coil, pressing firmly until the locking tab clicks into place. Verify each connection is secure by gently pulling on the connector body. Route wiring harnesses away from hot exhaust components and ensure no wires are pinched or stretched.
12. 12

    Reinstall engine cover and reconnect battery
    Position the engine cover over the engine, aligning the mounting grommets with the posts on the intake manifold and valve covers. Press down firmly until all grommets seat properly. Reconnect the negative battery cable to the battery terminal and tighten securely.

Reassembly

1. Verify all ignition coil electrical connectors are fully seated and locked
2. Confirm engine cover is properly seated on all mounting points
3. Double-check that no tools or parts were left in the engine bay
4. Ensure air filter housing lid is completely latched with all clips secured

Verification

• Start the engine and verify it starts smoothly without extended cranking
• Listen for smooth idle with no misfires, rough running, or check engine light
• Allow engine to warm to operating temperature and verify no unusual sounds or vibrations
• Perform a test drive and confirm improved throttle response and acceleration
• Check for any oil leaks around spark plug wells after test drive
• Scan for diagnostic trouble codes if check engine light illuminates - may indicate improper coil connection or plug installation

More procedures for this vehicle