🔧 Tucson - Spark Plug Replacement

Replacing the spark plugs on your Tucson helps restore smooth idle, easy starting, fuel economy, and proper ignition performance. The 2.0L engine uses coil-on-plug ignition, which means each spark plug has its own ignition coil sitting directly above it.

Difficulty Level: Beginner | Estimated Time: 1-2 hours

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⚠️ Safety & Precautions

• ⚠️ Work only on a cold engine. Aluminum cylinder heads can be damaged if spark plugs are removed while hot.
• ⚠️ Disconnect the negative battery cable before unplugging ignition coils.
• ⚠️ Keep dirt, tools, and loose hardware out of the spark plug wells.
• ⚠️ Do not overtighten spark plugs. The cylinder head threads are aluminum and can strip.
• ⚠️ Use only the correct replacement spark plugs for your Tucson. Do not install universal-fit plugs.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 3/8-inch drive ratchet
• 3/8-inch drive 6-inch extension
• 5/8-inch spark plug socket
• 3/8-inch drive torque wrench
• Flat-blade screwdriver
• Compressed air nozzle
• Spark plug gap gauge
• Needle-nose pliers
• Magnetic pickup tool
• Battery terminal wrench 10mm
• Nitrile 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, shift to Park, and set the parking brake.
• ❄️ Let the engine cool completely before starting.
• 🔋 Use a 10mm socket or battery terminal wrench to disconnect the negative battery cable.
• 🧼 Blow loose dirt away from the top of the engine with compressed air before removing parts.
• 📏 A spark plug gap gauge checks the distance between the center electrode and ground strap. Most modern plugs come pre-gapped, but they should still be inspected.
• 🧴 Dielectric grease is a non-conductive silicone grease used inside ignition coil boots to help prevent moisture and sticking.

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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.
• The cover is held by rubber grommets, not screws.
• Set the cover aside where it will not get stepped on.
• Pull evenly to avoid cracking it.

Step 2: Disconnect the Negative Battery Cable

• Use a 10mm socket or battery terminal wrench 10mm to loosen the negative battery terminal clamp.
• Lift the cable off the battery post and move it aside so it cannot spring back.
• This prevents accidental electrical shorts while unplugging ignition coils.

Step 3: Locate the Ignition Coils

• Look at the top center of the engine. You will see four ignition coils lined up front-to-back across the valve cover.
• Each ignition coil has an electrical connector and one retaining bolt.
• An ignition coil turns battery voltage into the high voltage needed to fire the spark plug.

Step 4: Unplug the Ignition Coil Connectors

• Use your thumb to press the locking tab on each ignition coil connector.
• If a connector is stuck, gently use a flat-blade screwdriver to help release the tab.
• Do not pull on the wires. Pull only on the connector body.
• Old plastic can break easily.

Step 5: Remove the Ignition Coils

• Use a 10mm socket and 3/8-inch drive ratchet to remove the ignition coil retaining bolts.
• Gently twist each ignition coil by hand, then pull it straight upward.
• If a coil boot sticks, use needle-nose pliers carefully on the boot area only if needed.
• Keep the coils in order so each one goes back into the same cylinder.
• During installation later, tighten each ignition coil bolt to Torque to 9.8 Nm (87 in-lbs).

Step 6: Clean the Spark Plug Wells

• Put on safety glasses.
• Use a compressed air nozzle to blow dirt and debris out of each spark plug well.
• A spark plug well is the deep tube where the spark plug sits.
• Do not skip this step. Dirt can fall into the engine when the plug is removed.

Step 7: Remove the Old Spark Plugs

• Install the 5/8-inch spark plug socket onto the 3/8-inch drive 6-inch extension.
• Attach the extension to the 3/8-inch drive 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 with the spark plug socket.
• If the plug falls out of the socket, use a magnetic pickup tool to remove it.

Step 8: Inspect and Check the New Spark Plugs

• Use a spark plug gap gauge to carefully check the gap on each new plug.
• Do not force the gauge between the electrodes.
• Do not pry on fine-wire iridium or platinum electrodes.
• If the plug gap is incorrect or the plug is damaged, replace it instead of bending it aggressively.
• Handle new plugs gently.

Step 9: 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 drive 6-inch extension.
• Turn the extension clockwise by hand only for the first several turns.
• If it does not turn smoothly, stop and back it out. This prevents cross-threading.
• Cross-threading means the plug is going in crooked and can damage the cylinder head.

Step 10: Torque the Spark Plugs

• Attach the 3/8-inch drive torque wrench to the 3/8-inch drive 6-inch extension and 5/8-inch spark plug socket.
• Tighten each spark plug to Torque to 18-22 Nm (13-16 ft-lbs).
• Do not add extra tightening after the torque wrench clicks.
• Do not use anti-seize unless the spark plug manufacturer specifically requires it.

Step 11: Apply Dielectric Grease

• Apply a small pea-sized amount of dielectric grease inside the end of each ignition coil boot.
• Use your gloved fingertip to spread it lightly around the inside of the boot opening.
• Do not fill the boot with grease.

Step 12: Reinstall the Ignition Coils

• Push each ignition coil straight down onto its spark plug until it seats fully.
• Use a 10mm socket to start each ignition coil retaining bolt by hand.
• Use the 3/8-inch drive torque wrench and 10mm socket to tighten each bolt to Torque to 9.8 Nm (87 in-lbs).

Step 13: Reconnect the Ignition Coil Connectors

• Push each ignition coil connector onto its coil until it clicks.
• Lightly tug the connector body by hand to confirm it is locked.
• Make sure the wiring is not pinched or stretched.

Step 14: Reinstall the Engine Cover

• Line up the engine cover with the rubber mounting points.
• Press down firmly by hand until the cover seats evenly.

Step 15: Reconnect the Battery

• Place the negative battery cable back onto the negative battery post.
• Use a 10mm socket or battery terminal wrench 10mm to tighten the terminal clamp snugly.
• Do not overtighten the battery terminal.

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✅ After Repair

• ✅ Start your Tucson and let it idle for 1-2 minutes.
• ✅ The engine should idle smoothly with no flashing check engine light.
• ✅ If the engine misfires, shut it off and recheck all ignition coil connectors.
• ✅ Take a short test drive and listen for smooth acceleration.
• ✅ If any warning lights remain, scan for diagnostic trouble codes before driving far.
• ✅ Some radio or clock settings may need to be reset after the battery disconnect.

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💰 DIY vs Shop Cost

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

DIY Cost: $45-$120 (parts only)

You Save: $135-$230 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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