This procedure covers the removal and replacement of all four ignition coils on the 2.5L I4 engine in 2016-2024 Hyundai Tucson AWD models.

Warnings

Tools required

Parts

• Ignition coil × 4 — Use OEM specification
• Spark plugs (if replacing) × 4 — Hyundai 18855-10080 or equivalent iridium

Preparation

1. Ensure engine is cool to the touch (wait at least 1 hour after running).
2. Disconnect negative battery terminal and wait 3 minutes to allow capacitors to discharge.
3. Gather all tools and parts before beginning work.
4. Take a photo of the engine cover and coil connector routing for reference during reassembly.

Procedure

1. 1

   Remove engine cover
   Remove the plastic engine cover by pulling upward firmly on the front edge to release the retaining clips. The cover typically has 4-6 rubber grommets that friction-fit to posts on the valve cover. Set the cover aside in a clean area.
2. 2

   Disconnect ignition coil electrical connectors
   Locate all four ignition coil connectors on top of the valve cover. Press the locking tab on each connector and pull straight up to disconnect. The connectors are color-coded and keyed to prevent incorrect installation. Note the orientation of each connector for reassembly.
3. 3

   Remove ignition coil mounting bolts
   Using a 10mm socket, remove the single bolt securing each ignition coil to the valve cover. Each coil has one bolt at the top of the unit. Keep bolts organized as they will be reused during installation.
   Torque spec

   Ignition Coil Bolts8 Nm (6 lb-ft)
4. 4

   Extract ignition coils
   Grasp each ignition coil firmly and pull straight upward with a twisting motion to break the rubber seal. The coil boot extends into the spark plug well and may require moderate force to remove. If stuck, gently twist back and forth while pulling upward. Do not use excessive force or pry against the valve cover.
   ⚠Do not damage the rubber boot on the bottom of the coil as this seals the spark plug well from debris and moisture.
5. 5

   Clean spark plug wells
   Use compressed air or a shop vacuum to remove any debris, oil, or dirt from each spark plug well before proceeding. Ensure the area around each spark plug is completely clean to prevent contamination from falling into the cylinder when plugs are removed.
   ⚠Any debris that falls into the cylinder can cause serious engine damage. Thoroughly clean each well before removing spark plugs.
6. 6

   Remove spark plugs (if replacing)
   If replacing spark plugs during this service, use a 16mm spark plug socket with extension to carefully remove each spark plug. Turn counterclockwise and keep the socket straight to avoid cross-threading. Inspect old plugs for unusual wear patterns that might indicate engine problems.
7. 7

   Inspect old ignition coils
   Examine the rubber boots on the removed coils for cracks, tears, or carbon tracking. Check the coil body for cracks or signs of overheating. Inspect the spring contact terminal inside each boot for corrosion or damage. These signs indicate why coils may have failed.
8. 8

   Install new spark plugs (if replacing)
   Apply a thin coat of anti-seize compound to the threads of each new spark plug, avoiding the electrode area. Hand-thread each plug into the cylinder head, turning clockwise until finger-tight to prevent cross-threading. Use the 16mm spark plug socket and torque wrench to tighten to specification.
   ⚠️CRITICAL: Over-torquing spark plugs in aluminum heads can strip threads and require expensive cylinder head repair. Use a calibrated torque wrench.
   Torque spec

   Spark Plugs - Aluminum Head20 Nm (15 lb-ft)
9. 9

   Prepare new ignition coils
   Apply a thin layer of dielectric grease to the inside of each new ignition coil rubber boot. This helps create a moisture seal and aids in future removal. Also apply a small amount of dielectric grease to the electrical connector terminals to prevent corrosion.
10. 10

    Install new ignition coils
    Insert each new ignition coil into its respective spark plug well, ensuring the boot slides completely over the spark plug terminal. Push down firmly until the coil seats flush against the valve cover mounting surface. The coil should drop into place with moderate pressure and a slight click.
11. 11

    Secure ignition coils
    Install the mounting bolt for each ignition coil and hand-tighten. Using a torque wrench and 10mm socket, torque each bolt to specification in a cross-pattern sequence (cylinder 1, 4, 2, 3) to ensure even seating.
    Torque spec

    Ignition Coil Bolts8 Nm (6 lb-ft)
12. 12

    Reconnect electrical connectors
    Push each electrical connector onto its corresponding ignition coil until you hear and feel a distinct click indicating the locking tab has engaged. Gently tug on each connector to verify it is securely locked. Ensure wiring routing matches your reference photo.
13. 13

    Reinstall engine cover
    Align the engine cover grommets with the posts on the valve cover. Press down firmly on each grommet location until all clips are fully seated. The cover should sit flush with no gaps.

Reassembly

1. Reconnect the negative battery terminal and tighten securely.
2. Ensure all electrical connectors are fully engaged with audible clicks.
3. Verify the engine cover is properly seated and all tools are removed from the engine bay.

Verification

• Start the engine and verify it runs smoothly without misfires or rough idle.
• Check that the check engine light does not illuminate and no misfire codes are present.
• Listen for any unusual arcing sounds that might indicate a poor coil connection.
• Perform a brief test drive and verify smooth acceleration without hesitation or stumbling.
• After test drive, inspect around each coil for any signs of oil leaks from the valve cover.

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