This procedure addresses a data mismatch: the 2018-2024 Toyota Camry with a 2.5L I4 engine does not have a V6 configuration. This guide provides spark plug replacement for the actual 2.5L inline-4 engine.

Warnings

Tools required

Parts

• Spark plugs (iridium) × 4 — 90919-01253 or equivalent NGK ILKAR8J8
• Ignition coil gaskets/seals (if equipped) × 4 — Use OEM specification

Preparation

1. Ensure engine is completely cold (allow at least 2 hours after last operation).
2. Park vehicle on level surface and engage parking brake.
3. Disconnect negative battery terminal to prevent electrical shorts.
4. Gather all tools and new spark plugs before beginning.

Procedure

1. 1

   Remove engine cover
   Locate and remove the plastic engine cover. On the 2.5L I4, this typically has 4-6 friction clips or fasteners. Gently pull upward on the cover to release the clips. If equipped with bolts, remove them using a 10mm socket.
   Torque spec

   Engine Cover Clips3 Nm (2 lb-ft)
2. 2

   Access ignition coils
   Locate all four ignition coils on top of the engine. Each coil sits directly above a spark plug. Note their positions and any wiring harness routing for reassembly. The 2.5L I4 has all four coils easily accessible from the top.
3. 3

   Disconnect ignition coil electrical connectors
   Press the locking tab on each ignition coil electrical connector and pull straight up to disconnect. Do not pull on the wires themselves. Mark or photograph connector positions if needed for reference.
4. 4

   Remove ignition coils
   Remove the single 10mm bolt securing each ignition coil. Carefully pull each coil straight up and out of the spark plug well. Resistance is normal due to the rubber boot seal. If stuck, gently twist while pulling. Set coils aside in order.
   Torque spec

   Ignition Coil Bolt11 Nm (8 lb-ft)
5. 5

   Clean spark plug wells
   Use compressed air or a vacuum to remove any debris, dirt, or oil from each spark plug well before removing plugs. This prevents contaminants from entering the combustion chamber. Inspect for oil pooling which may indicate valve cover gasket issues.
   ⚠Even small debris falling into the cylinder can cause severe engine damage. Ensure wells are completely clean.
6. 6

   Remove old spark plugs
   Using the spark plug socket and extension, carefully loosen each spark plug by turning counterclockwise. Initial break-loose requires firm pressure. Once loose, unthread by hand to prevent cross-threading. Remove all four plugs and inspect them for wear, deposits, or damage.
7. 7

   Inspect old spark plugs
   Examine the removed plugs for electrode wear, carbon deposits, oil fouling, or abnormal burning patterns. Normal plugs show light tan or gray deposits. Excessive wear, oil, or unusual coloring may indicate engine issues requiring attention.
8. 8

   Gap new spark plugs
   Check and adjust the electrode gap on all new spark plugs using a gap tool. The 2018-2024 Camry 2.5L I4 typically requires 0.039-0.043 inches (1.0-1.1mm). Verify specification on underhood label or owner's manual. Pre-gapped plugs should still be verified.
   ℹ️Incorrect gap can cause misfires, poor fuel economy, and emission failures.
9. 9

   Apply anti-seize to spark plug threads
   Apply a thin, even coat of anti-seize compound to the threads of each new spark plug, avoiding the electrode area. Use sparingly - excess can foul the plug or contaminate the combustion chamber. This is critical for aluminum cylinder heads to prevent thread seizure.
   ⚠Do not apply anti-seize to the electrode or insulator. Keep compound on threads only.
   Torque spec

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

    Install new spark plugs
    Carefully thread each new spark plug by hand into the cylinder head, turning clockwise. Thread at least 3-4 full turns by hand to ensure proper alignment. If resistance is felt, stop and restart - never force. Once hand-tight, use the torque wrench to tighten to specification.
    ⚠️Cross-threading spark plugs in the aluminum head will require expensive thread repair or cylinder head replacement. Always start by hand.
    Torque spec

    Spark Plug20 Nm (15 lb-ft)
11. 11

    Apply dielectric grease and reinstall ignition coils
    Apply a small amount of dielectric grease to the inside of each ignition coil boot (optional but recommended). Carefully push each coil straight down into its spark plug well until fully seated. Reinstall and torque the mounting bolt for each coil.
    Torque spec

    Ignition Coil Bolt11 Nm (8 lb-ft)
12. 12

    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.
13. 13

    Reinstall engine cover
    Position the engine cover and align all clips or fasteners. Press down firmly at each clip location until fully seated, or install and tighten any bolts to specification. Ensure cover is secure and properly aligned.
    Torque spec

    Engine Cover Clips3 Nm (2 lb-ft)
14. 14

    Reconnect battery and clear codes
    Reconnect the negative battery terminal. If the vehicle has stored any misfire codes from previous spark plug wear, clear them using an OBD-II scanner or allow several drive cycles for the ECU to relearn.

Reassembly

1. Ensure all ignition coil connectors are fully seated and locked.
2. Verify engine cover is properly installed with all clips engaged.
3. Double-check that no tools or parts were left in the engine bay.

Verification

• Start the engine and listen for smooth idle with no misfires or rough running.
• Allow engine to reach operating temperature and verify smooth acceleration.
• Check for diagnostic trouble codes using an OBD-II scanner - there should be no misfire codes.
• Perform a test drive under various loads to confirm proper engine performance and throttle response.
• Inspect for any visible spark or arcing around ignition coils after dark if possible.

More procedures for this vehicle