🔧 Spark Plugs - Replacement

Replacing the spark plugs on your Tucson helps restore smooth idle, easier starting, fuel economy, and proper ignition performance. The 2.0L inline-4 uses four spark plugs, one for each cylinder, located under the ignition coils on top of the engine.

Difficulty Level: Beginner | Estimated Time: 45 minutes-1.5 hours

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⚠️ Safety & Precautions

• ⚠️ Work only on a completely cool engine so the aluminum cylinder head threads are not damaged.
• ⚠️ Disconnect the negative battery cable before unplugging ignition coils.
• ⚠️ Keep dirt, bolts, and tools away from the open spark plug wells.
• ⚠️ Do not overtighten spark plugs; the cylinder head is aluminum and threads can strip.
• ⚠️ Use only the correct plug type for your Tucson. Do not install random “universal” plugs.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 3/8-inch ratchet
• 3/8-inch extension 6-inch
• 5/8-inch spark plug socket
• Torque wrench 5-30 ft-lbs
• Spark plug gap gauge
• Needle-nose pliers
• Compressed air blow gun
• Battery terminal wrench 10mm
• Dielectric grease applicator
• Mechanic gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs - Qty: 4
• Dielectric grease - Qty: 1

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📋 Before You Begin

• Park your Tucson on level ground and let the engine cool fully.
• Set the parking brake and place the manual transmission in neutral.
• Open the hood and remove the key from the ignition.
• Use a 10mm battery terminal wrench to disconnect the negative battery cable.
• A spark plug socket is a deep socket with a rubber insert or magnet that holds the spark plug so it does not fall.
• Dielectric grease is a non-conductive silicone grease used inside the coil boot to keep moisture out.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the Engine Cover

• Use both hands to lift the plastic engine cover straight upward.
• If fasteners are fitted, use a 10mm socket and 3/8-inch ratchet to remove them.
• Set the cover aside where it will not be stepped on.
• Tip: Pull straight up, not sideways.

Step 2: Clean Around the Ignition Coils

• Put on safety glasses.
• Use a compressed air blow gun to blow dirt away from the top of the engine and around each ignition coil.
• This keeps debris from falling into the spark plug holes after the coils are removed.

Step 3: Unplug the Ignition Coil Connectors

• Each spark plug has one ignition coil mounted above it.
• An ignition coil is the small electrical part that creates the high voltage needed to fire the spark plug.
• Use your fingers to press the release tab on the coil connector.
• If the connector is tight, use needle-nose pliers gently on the locking tab only.
• Pull the connector straight back. Do not pull on the wires.

Step 4: Remove the Ignition Coils

• Use a 10mm socket, 3/8-inch extension 6-inch, and 3/8-inch ratchet to remove the hold-down bolt from each ignition coil.
• Twist each coil slightly by hand to loosen the rubber boot.
• Pull each coil straight upward and set it aside in order.
• Keeping them in order helps you put each coil back in the same cylinder.

Step 5: Remove the Old Spark Plugs

• Use a 5/8-inch spark plug socket, 3/8-inch extension 6-inch, and 3/8-inch ratchet.
• Lower the socket straight down into the first spark plug well.
• Turn counterclockwise slowly to loosen the spark plug.
• Once loose, spin it out by hand using the extension.
• Lift the spark plug out carefully with the socket.
• Repeat for all four spark plugs.
• Tip: If it binds, stop and retighten slightly.

Step 6: Check the New Spark Plugs

• Use a spark plug gap gauge to verify the plug gap before installation.
• The plug gap is the small space between the center electrode and the ground strap at the tip of the spark plug.
• For your Tucson, set the spark plug gap to approximately 1.0-1.1 mm / 0.039-0.043 inch, unless the plug maker says the plug is pre-gapped and not adjustable.
• Do not pry on fine-tip iridium or platinum spark plugs.

Step 7: Install the New Spark Plugs by Hand

• Place one new spark plug into the 5/8-inch spark plug socket.
• Lower it straight into the spark plug well using the 3/8-inch extension 6-inch.
• Turn the extension clockwise by hand only for several turns.
• This prevents cross-threading, which means the plug is going in crooked and damaging the threads.
• If it does not turn easily by hand, remove it and try again.

Step 8: Torque the Spark Plugs

• Attach a torque wrench 5-30 ft-lbs to the 5/8-inch spark plug socket and 3/8-inch extension 6-inch.
• Tighten each spark plug to Torque to 18-22 Nm (13-16 ft-lbs).
• Do not add extra tightening after the torque wrench clicks.
• Tip: One click is enough.

Step 9: Reinstall the Ignition Coils

• Apply a very small amount of dielectric grease inside each coil boot using a dielectric grease applicator.
• Push each ignition coil straight down over its spark plug until seated.
• Install each coil hold-down bolt using a 10mm socket, 3/8-inch extension 6-inch, and 3/8-inch ratchet.
• Tighten the ignition coil bolts to Torque to 8-10 Nm (71-89 in-lbs).

Step 10: Reconnect the Coil Connectors

• Push each electrical connector onto its ignition coil until it clicks.
• Gently tug each connector by hand to make sure it is locked.
• Use needle-nose pliers only if a connector lock needs light help seating.

Step 11: Reinstall the Engine Cover

• Line up the engine cover with its mounting points.
• Press it straight down by hand until seated.
• If fasteners are fitted, use a 10mm socket and 3/8-inch ratchet to reinstall them snugly.

Step 12: Reconnect the Battery

• Use a 10mm battery terminal wrench to reconnect the negative battery cable.
• Tighten the terminal snugly so it cannot twist by hand.

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✅ After Repair

• Start your Tucson and let it idle for 1-2 minutes.
• Listen for a smooth idle with no shaking or misfire.
• If the engine runs rough, shut it off and recheck that all four coil connectors are fully clicked in.
• Take a short test drive and confirm smooth acceleration.
• If a check engine light appears, scan for codes before driving much farther.

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💰 DIY vs Shop Cost

Shop Cost: $160-$300 (parts + labor)

DIY Cost: $35-$90 (parts only)

You Save: $125-$210 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.8-1.2 hours.

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🎯 Ready to get started?

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