🔧 Tucson - Spark Plug Replacement

Replacing the spark plugs on your Tucson helps restore smooth starting, clean idle, 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: 1-2 hours

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⚠️ Safety & Precautions

• ⚠️ Let the engine cool completely before starting. Spark plugs thread into the aluminum cylinder head, and hot aluminum is easier to damage.
• ⚠️ Disconnect the negative battery cable to reduce the chance of an accidental short while unplugging ignition coils.
• ⚠️ Work on one cylinder at a time so the ignition coils and connectors stay organized.
• ⚠️ Do not force a spark plug. Cross-threading means the plug is going in crooked and can damage the engine head.
• ⚠️ Do not use anti-seize on modern plated spark plug threads unless the plug manufacturer specifically requires it.

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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 3/8-inch drive
• Needle-nose pliers
• Compressed air blower nozzle
• Spark plug gap gauge
• Dielectric grease
• Fender cover
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Iridium spark plugs - Qty: 4

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📋 Before You Begin

• 🅿️ Park your Tucson on level ground, shift to Park, and set the parking brake.
• ❄️ Let the engine cool until it is safe to touch with bare hands.
• 🔋 Disconnect the negative battery cable using a 10mm socket. The negative cable is usually marked with a minus symbol.
• 🧼 Clean loose dirt from the top of the engine so debris does not fall into the spark plug wells.
• 📏 Check the new spark plug gap only if the plug maker says it is adjustable. A gap gauge measures the space between the center electrode and ground strap.

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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 your Tucson has the snap-on cover.
• If fasteners are installed, use a 10mm socket and 3/8-inch ratchet to remove them.
• Set the cover aside where it will not get stepped on.
• Tip: Take a photo first.

Step 2: Locate the Ignition Coils

• Find the four ignition coils on top of the engine. An ignition coil is the small electrical unit that sends spark to each spark plug.
• Each coil has an electrical connector and one hold-down bolt.
• Work on one coil and one spark plug at a time.

Step 3: Disconnect the First Ignition Coil Connector

• Press the connector lock tab with your thumb and gently pull the connector straight back.
• If the connector is tight, use needle-nose pliers carefully on the connector body, not the wires.
• Do not pull on the wiring harness.

Step 4: Remove the Ignition Coil

• Use a 10mm socket, 3/8-inch ratchet, and 3/8-inch extension 6-inch to remove the coil hold-down bolt.
• Twist the ignition coil gently left and right, then pull it straight upward.
• Set the coil on a clean surface in the same orientation it came out.

Step 5: Clean the Spark Plug Well

• Put on safety glasses.
• Use a compressed air blower nozzle to blow dirt out of the spark plug well.
• This prevents grit from falling into the cylinder when the plug is removed.
• Tip: Dirt is engine enemy.

Step 6: Remove the Old Spark Plug

• Place the 5/8-inch spark plug socket onto the 3/8-inch extension 6-inch and 3/8-inch ratchet.
• Lower the socket straight down onto the spark plug.
• Turn counterclockwise slowly to loosen the plug.
• Once loose, spin it out by hand using the extension.
• Lift the old spark plug out with the spark plug socket. A spark plug socket has a rubber insert or magnet to hold the plug.

Step 7: Inspect the Old Spark Plug

• Look at the tip of the old plug.
• Light tan or gray is usually normal.
• Oil-soaked, fuel-wet, cracked, or heavily white deposits can point to another engine issue.
• Compare it with the new iridium spark plug before installing.

Step 8: Check the New Spark Plug

• Use a spark plug gap gauge only to verify the gap if needed. Do not pry on fine-wire iridium tips.
• Make sure the new spark plug is clean and the porcelain is not cracked.
• Do not apply anti-seize unless the spark plug manufacturer specifically calls for it.

Step 9: Install the New Spark Plug by Hand

• Insert the new iridium 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 clockwise by hand only for the first several turns.
• If it does not spin in smoothly, stop, remove it, and restart.
• Tip: Hand-start every plug.

Step 10: Torque the Spark Plug

• Attach the torque wrench 3/8-inch drive to the 5/8-inch spark plug socket and 3/8-inch extension 6-inch.
• Tighten the spark plug to Torque to 18-25 Nm (13-18 ft-lbs).
• Do not overtighten. The cylinder head is aluminum.

Step 11: Reinstall the Ignition Coil

• Apply a small pea-sized amount of dielectric grease inside the rubber boot opening. Dielectric grease helps seal out moisture but does not conduct electricity.
• Push the ignition coil straight down until it seats fully on the spark plug.
• Install the coil hold-down bolt using a 10mm socket and 3/8-inch ratchet.
• Tighten the ignition coil bolt to Torque to 8-10 Nm (71-89 in-lbs).

Step 12: Reconnect the Ignition Coil Connector

• Push the electrical connector onto the ignition coil until it clicks.
• Gently tug the connector to make sure it is locked.

Step 13: Repeat for the Other Three Spark Plugs

• Repeat Steps 3 through 12 for the remaining three cylinders.
• Use the same 10mm socket, 5/8-inch spark plug socket, 3/8-inch extension 6-inch, and torque wrench 3/8-inch drive.
• Replace all four spark plugs as a set.

Step 14: Reinstall the Engine Cover

• Position the engine cover over its mounting points.
• Push it straight down until it snaps in place.
• If bolts were removed, install them with a 10mm socket and 3/8-inch ratchet.

Step 15: Reconnect the Battery

• Reconnect the negative battery cable.
• Use a 10mm socket to snug the terminal clamp.
• Do not overtighten the battery terminal.

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✅ After Repair

• ✅ Start the engine and let it idle for one to two minutes.
• ✅ The idle may be slightly different at first after the battery was disconnected, then should smooth out.
• ✅ Listen for misfires, ticking, or popping sounds.
• ✅ If the check engine light flashes, shut the engine off and recheck that all four coil connectors are fully seated.
• ✅ Take a short test drive and confirm smooth acceleration.
• ✅ Recheck that the engine cover is secure after the test drive.

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💰 DIY vs Shop Cost

Shop Cost: $180-$350 (parts + labor)

DIY Cost: $40-$100 (parts only)

You Save: $140-$250 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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