🔧 Tucson - Spark Plug Replacement

Replacing the spark plugs on your Tucson helps restore smooth starting, steady idle, fuel economy, and proper ignition performance. The 2.0L engine uses one ignition coil per spark plug, so you’ll remove the coils first, then replace the plugs underneath.

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

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⚠️ Safety & Precautions

• ⚠️ Work only on a completely cool engine to avoid burns and prevent damaging aluminum cylinder head threads.
• ⚠️ Disconnect the negative battery cable before unplugging ignition coils to reduce the chance of electrical shorting.
• ⚠️ Do not drop anything into the spark plug wells. Dirt or hardware can enter the engine when the plug is removed.
• ⚠️ Do not overtighten spark plugs. The cylinder head is aluminum and threads can strip if over-torqued.
• ⚠️ Replace spark plugs one at a time if you are nervous. This helps keep everything organized.

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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
• Torque wrench rated 5-30 ft-lbs
• Spark plug gap gauge
• Compressed air nozzle
• Needle-nose pliers
• Plastic trim removal tool
• Shop vacuum
• Clean shop towels
• 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
• Dielectric grease - Qty: 1 small tube

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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 fully. A cool engine protects the spark plug threads in the aluminum cylinder head.
• Open the hood and remove the key from the vehicle.
• Use a 10mm socket to loosen the negative battery terminal, then move the cable aside so it cannot spring back onto the battery post.
• A spark plug socket is a deep socket with a rubber insert or magnet that grips the spark plug so you can lift it out safely.
• A torque wrench is a tool that tightens a bolt or spark plug to a measured force so it is not too loose or too tight.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the Engine Cover

• Put on safety glasses and nitrile gloves.
• Grip the plastic engine cover with both hands and pull upward evenly.
• If it feels stuck, use a plastic trim removal tool to gently help lift the cover at the rubber mounting points.
• Set the cover aside on a clean towel.
• Lift straight up, not sideways.

Step 2: Clean Around the Ignition Coils

• Use a shop vacuum to remove loose dirt from the top of the engine.
• Use a compressed air nozzle to blow dirt away from the four ignition coil areas.
• The ignition coil is the black electrical part sitting directly above each spark plug.
• Wipe the area with clean shop towels before opening the spark plug wells.

Step 3: Disconnect the Ignition Coil Connectors

• Use your fingers to press the locking tab on the first ignition coil connector.
• If the connector is tight, use needle-nose pliers gently on the connector body, not the wires.
• Pull the connector straight back from the coil.
• Repeat for all four ignition coil connectors.
• Never pull on the wires.

Step 4: Remove the Ignition Coils

• Use a 10mm socket, 3/8-inch drive ratchet, and 6-inch extension to remove the ignition coil retaining bolt from the first coil.
• Pull the ignition coil straight up with a gentle twisting motion.
• Set each coil in order from left to right so it can go back into the same cylinder.
• Repeat for the remaining three coils.
• During installation later, tighten each ignition coil bolt to Torque to 9.8 Nm (7 ft-lbs).

Step 5: Remove the First Spark Plug

• Use a compressed air nozzle to blow out the first spark plug well before removing the plug.
• Install the 5/8-inch spark plug socket onto the 6-inch extension and 3/8-inch drive ratchet.
• Lower the socket straight down onto the spark plug.
• Turn counterclockwise to loosen the spark plug.
• Once loose, spin it out slowly and lift it out with the spark plug socket.
• If the plug feels stuck, stop and tighten it slightly, then loosen again slowly.
• Slow is safer for threads.

Step 6: Check the New Spark Plug

• Use a spark plug gap gauge to verify the new spark plug gap is about 1.0-1.1 mm (0.039-0.043 in).
• Do not forcefully bend the tip on iridium spark plugs. Iridium tips are delicate.
• Do not apply anti-seize unless the spark plug manufacturer specifically says to. Most modern iridium plugs are already coated.
• Check that the small metal washer is on the new spark plug.

Step 7: Install the New Spark Plug by Hand First

• Place the new spark plug into the 5/8-inch spark plug socket.
• Lower it straight into the spark plug well using the 6-inch extension only, without the ratchet attached at first.
• Turn the extension clockwise by hand for several turns.
• If it does not turn easily, stop, remove it, and start again. This prevents cross-threading, which means the plug is going in crooked.
• Attach the torque wrench rated 5-30 ft-lbs with the 5/8-inch spark plug socket.
• Tighten the spark plug to Torque to 18-22 Nm (13-16 ft-lbs).

Step 8: Repeat for the Other Three Spark Plugs

• Use the compressed air nozzle before removing each spark plug.
• Use the 5/8-inch spark plug socket, 6-inch extension, and 3/8-inch drive ratchet to remove each old plug.
• Use the spark plug gap gauge to verify each new plug before installation.
• Start each new spark plug by hand with the 6-inch extension.
• Use the torque wrench to tighten each spark plug to Torque to 18-22 Nm (13-16 ft-lbs).
• One plug at a time keeps it simple.

Step 9: Reinstall the Ignition Coils

• Apply a small pea-sized amount of dielectric grease inside each ignition coil boot.
• Dielectric grease is a non-conductive grease that helps seal out moisture and makes future removal easier.
• Push each ignition coil straight down onto its spark plug until it seats fully.
• Use the 10mm socket, 6-inch extension, and torque wrench to install each coil bolt.
• Tighten each ignition coil bolt to Torque to 9.8 Nm (7 ft-lbs).

Step 10: Reconnect the Ignition Coil Connectors

• Push each electrical connector onto its ignition coil by hand until it clicks.
• Use your fingers to lightly tug each connector body to confirm it is locked.
• If a connector does not click, inspect the locking tab before starting the engine.

Step 11: Reinstall the Engine Cover and Battery Cable

• Align the engine cover over its rubber mounting points.
• Press down firmly by hand until the cover snaps into place.
• Reconnect the negative battery cable.
• Use a 10mm socket to snug the negative battery terminal. Do not overtighten it.

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✅ After Repair

• Start your Tucson and let it idle for 1-2 minutes.
• Listen for smooth running. A slight high idle for a short time can happen after battery disconnect.
• If the engine shakes or the check engine light flashes, shut it off and recheck the ignition coil connectors.
• Take a short test drive around the block and confirm smooth acceleration.
• After the test drive, open the hood and make sure the engine cover is secure.

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💰 DIY vs Shop Cost

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

DIY Cost: $45-$100 (parts only)

You Save: $135-$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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