This procedure addresses a mismatch: the vehicle is equipped with a 2.5L I4 engine, but the job requests V6 spark plug replacement. The 2.5L I4 has inline 4-cylinder spark plug access, not V6 configuration.

Warnings

Tools required

Parts

• Spark plugs (iridium) × 4 — 90919-02260 or equivalent
• Ignition coil gaskets/seals × 4 — Use OEM specification

Preparation

1. Ensure engine is completely cool to the touch (minimum 2 hours after last operation)
2. Park vehicle on level surface and engage parking brake
3. Disconnect negative battery terminal and wait 3 minutes for airbag system discharge
4. Gather all tools and new spark plugs
5. Verify new spark plugs match specification for 2012-2017 Camry 2.5L I4

Procedure

1. 1

   Remove engine cover
   Grasp the engine cover firmly at the front and rear pull points. Pull straight upward to release the four retaining clips from their grommets. The cover should release with moderate force. Set cover aside in clean area.
2. 2

   Disconnect ignition coils
   Locate all four ignition coils mounted directly over each spark plug. Press down on the electrical connector locking tab on each coil and pull the connector straight away from the coil. Mark or photograph coil positions if they appear different to ensure correct reinstallation order.
3. 3

   Remove ignition coil mounting bolts
   Using a 10mm socket, remove the single bolt securing each ignition coil. Keep bolts organized by cylinder position. Inspect bolt threads for damage.
   Torque spec

   Ignition Coil Bolt11 Nm (8 lb-ft)
4. 4

   Extract ignition coils
   Grasp each ignition coil firmly and pull straight upward with steady pressure. The coil may require slight twisting motion to break the seal. Remove all four coils and inspect the rubber boot on each coil for cracks, tears, or carbon tracking. Replace coils if boots are damaged.
   ⚠If boots are stuck, use a specialized coil boot puller tool. Excessive force can damage coils or break boots, leaving debris in spark plug wells.
5. 5

   Clean spark plug wells
   Use compressed air to blow debris away from spark plug wells (not into them). If compressed air is unavailable, use a vacuum with narrow attachment to clean around each spark plug. Inspect wells for oil accumulation which may indicate valve cover gasket leakage.
   ⚠Never blow compressed air directly into spark plug wells. Direct air around the perimeter to push debris outward, away from the opening.
6. 6

   Remove old spark plugs
   Using a 5/8" spark plug socket with rubber insert and extension, carefully place socket over first spark plug. Turn counterclockwise to loosen, then unthread by hand once loose. Remove plug completely and inspect electrode wear and fouling condition. Repeat for remaining three cylinders. Keep plugs in order for diagnostic purposes.
   ℹ️Spark plug condition can indicate engine issues: oil fouling suggests oil consumption, heavy carbon indicates rich mixture, white deposits suggest lean condition.
7. 7

   Inspect spark plug wells and threads
   Use flashlight to inspect each spark plug well for accumulated oil, coolant, or debris. Check threads in cylinder head for damage using a bright light. If threads appear damaged, stop and consult a thread repair specialist before proceeding.
8. 8

   Gap and prepare new spark plugs
   Verify gap on all new spark plugs using gap tool. Factory gap should be 0.043" (1.1mm) but verify against specification. Apply thin coating of anti-seize compound to the threads only (first 3-4 threads). Do not apply anti-seize to electrode end or allow it to contact electrode area.
   ⚠Excessive anti-seize or anti-seize on electrodes can cause pre-ignition and engine damage. Apply sparingly only to threads.
   Torque spec

   Spark Plug20 Nm (15 lb-ft)
9. 9

   Install new spark plugs
   Carefully thread first spark plug into cylinder head by hand, using extension and socket. Ensure plug threads smoothly without resistance. If resistance is felt, remove and restart - do not force. Once plug is hand-tight (seated against washer), use torque wrench to tighten to specification. Repeat for remaining three plugs.
   ⚠️Cross-threading spark plugs will destroy aluminum cylinder head threads, requiring extremely expensive repairs. Always start by hand and verify smooth threading.
   Torque spec

   Spark Plug20 Nm (15 lb-ft)
10. 10

    Inspect and prepare ignition coils
    Inspect rubber boot inside each ignition coil. Replace coil if boot shows cracks, carbon tracking, or damage. Apply thin coating of dielectric grease to inside of each boot to prevent moisture intrusion and ease future removal. Replace any damaged coil gaskets/seals.
11. 11

    Reinstall ignition coils
    Align each ignition coil over its corresponding spark plug. Push coil straight down firmly until fully seated - you should feel the boot snap over the spark plug terminal. Ensure coil mounting bolt hole aligns with cylinder head threaded hole.
    ⚠Partially seated ignition coils will cause misfires and can damage coils and spark plugs. Verify each coil is fully bottomed in its well.
12. 12

    Install ignition coil mounting bolts
    Thread each 10mm coil mounting bolt by hand to avoid cross-threading. Tighten all four bolts to specification using torque wrench in a crossing pattern (cylinders 1-4-2-3).
    Torque spec

    Ignition Coil Bolt11 Nm (8 lb-ft)
13. 13

    Reconnect electrical connectors
    Push each electrical connector onto its corresponding ignition coil until the locking tab clicks into place. Gently tug on each connector to verify it is locked. Verify no connectors are swapped between cylinders.
14. 14

    Reinstall engine cover and reconnect battery
    Align engine cover mounting grommets with the four mounting posts on valve cover. Press down firmly on each corner until all clips snap into place. Reconnect negative battery terminal and tighten securely.

Reassembly

1. Ensure all four ignition coil electrical connectors are fully locked
2. Verify engine cover is securely clipped at all four mounting points
3. Double-check that no tools or parts were left in engine compartment

Verification

• Start engine and verify it runs smoothly without misfires or rough idle
• Allow engine to reach operating temperature and verify no misfires occur under load
• Use OBD-II scanner to verify no misfire codes are present (P0300-P0304)
• Listen for unusual sounds indicating loose ignition coils or damaged components
• Inspect spark plug wells with flashlight for any dropped debris or improperly seated coils

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