Replace spark plugs on the 2016-2024 Hyundai Tucson 2.5L I4 AWD engine to restore ignition performance and maintain fuel efficiency.

Warnings

Tools required

Parts

• Spark plugs (4) × 4 — Use OEM specification or equivalent iridium plugs

Preparation

1. Park vehicle on level surface and engage parking brake
2. Ensure engine is completely cold to the touch
3. Gather all tools and parts before starting
4. Verify spark plug gap specification for your specific model year (typically 0.039-0.043 inches)
5. Open hood and secure with prop rod

Procedure

1. 1

   Remove engine cover
   Locate and remove the plastic engine cover by lifting the clips at each corner. Some models may have fasteners that require removal with a 10mm socket. Set the cover aside in a clean area.
   Torque spec

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

   Access ignition coils
   Identify all four ignition coils mounted directly above the spark plugs. The coils are arranged in a row along the top of the engine. Disconnect the electrical connector from each ignition coil by pressing the release tab and pulling straight up.
   ℹ️Mark or photograph coil locations if connectors are not keyed to prevent incorrect reassembly
3. 3

   Remove ignition coils
   Remove the single bolt securing each ignition coil using a 10mm socket. Carefully pull each coil straight up and out of the spark plug well. If resistance is felt, gently twist while pulling. Set coils in order to maintain proper orientation.
   Torque spec

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

   Clean spark plug wells
   Use compressed air to blow out any debris, dirt, or oil from around the spark plug wells. If compressed air is unavailable, carefully wipe the area with a clean rag. Ensure no foreign material falls into the cylinder when the plug is removed.
   ⚠Any debris that falls into the cylinder can cause serious engine damage
5. 5

   Remove old spark plugs
   Using the appropriate spark plug socket with extension, carefully loosen each spark plug by turning counterclockwise. Once loose, unthread by hand to prevent cross-threading. Remove all four plugs and inspect for unusual wear, oil fouling, or deposits that may indicate engine issues.
   ℹ️Examine old plugs for abnormal electrode wear, carbon buildup, or oil contamination which may require further diagnosis
6. 6

   Prepare new spark plugs
   Verify the gap on each new spark plug using a gap tool, even if they are pre-gapped. Adjust if necessary to meet manufacturer specifications (typically 0.039-0.043 inches). Optionally apply a small amount of anti-seize compound to the threads, avoiding the electrode area.
   ⚠Use anti-seize sparingly - excess compound can cause fouling or interfere with heat transfer
7. 7

   Install new spark plugs
   Carefully thread each new spark plug by hand into the cylinder head, turning clockwise. Ensure the plug threads in smoothly without resistance. If resistance is felt, back out and restart to avoid cross-threading. Once hand-tight, use the torque wrench and spark plug socket to tighten to specification.
   ⚠Cross-threading or over-torquing will damage the aluminum cylinder head threads, requiring costly repair
   Torque spec

   Spark Plug20 Nm (15 lb-ft)
8. 8

   Reinstall ignition coils
   Apply a small amount of dielectric grease to the inside of each ignition coil boot if desired. Carefully insert each coil back into its respective spark plug well, ensuring it seats fully onto the spark plug. Install and hand-tighten the mounting bolt, then torque to specification using a torque wrench.
   Torque spec

   Ignition Coil Bolt11 Nm (8 lb-ft)
9. 9

   Reconnect electrical connectors
   Reconnect the electrical connector to each ignition coil, ensuring each connector clicks securely into place. Verify all four connections are fully seated.
   ℹ️Loose or incorrectly connected coil connectors will cause misfires and check engine light
10. 10

    Reinstall engine cover
    Position the engine cover back onto the engine, aligning all mounting points. Press down firmly on each clip location until they snap into place, or install any fasteners that were removed, torquing to specification if applicable.
    Torque spec

    Engine Cover Clips3 Nm (2 lb-ft)

    Cover Screws11 Nm (8 lb-ft)

Reassembly

1. Ensure all ignition coil electrical connectors are fully seated and locked
2. Verify engine cover is properly secured at all mounting points
3. Perform a visual inspection to ensure 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
• Check that no warning lights (check engine or misfire) are illuminated on the dashboard
• Rev the engine gently to verify smooth acceleration and no hesitation
• After initial test, shut off engine and inspect for any fuel or oil leaks around spark plug area
• Take a short test drive to confirm normal engine performance under load

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