🔧 Tucson - Spark Plug Replacement

On your Tucson, the spark plugs sit under the ignition coils on top of the engine. Replacing them restores smooth starts, fuel economy, and prevents misfires as the plugs wear out over time.

Difficulty Level: Intermediate | Estimated Time: 1.0-2.0 hours

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⚠️ Safety & Precautions

• ⚠️ Work on a fully cool engine to avoid burns and prevent plug-thread damage in a hot cylinder head.
• ⚠️ If you disconnect the battery, use a 10mm wrench and remove the negative terminal first.
• ⚠️ Do not pull on wiring; release electrical locks and pull on connectors.
• ⚠️ Keep dirt out of the plug holes—debris can fall into the cylinder.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 3/8" drive ratchet
• 3/8" drive extension set
• 5/8" spark plug socket
• Torque wrench (3/8" drive)
• Small flathead screwdriver
• Needle-nose pliers
• Compressed air blow gun
• Feeler gauge set
• Clean shop towels
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs (iridium/platinum, correct for Tucson 2.4L) - Qty: 4
• Dielectric grease - Qty: 1

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📋 Before You Begin

• Park on level ground, shift to Park, and set the parking brake.
• Let the engine cool completely (at least 1 hour if it was hot).
• Set your new plugs aside in a clean area so nothing contaminates the tips.
• If you choose to disconnect the battery: use a 10mm wrench and remove the negative terminal first.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover (if equipped)

• Grip the cover and pull upward to release the rubber grommets.
• Set it aside so you can clearly see the 4 ignition coils on top of the engine.

Step 2: Unplug and remove the ignition coils

• At the first coil, press the electrical connector lock and pull the connector straight off.
• If the lock is stubborn, gently help it with a small flathead screwdriver.
• Remove the coil retaining bolt using a 10mm socket with a 3/8" drive ratchet.
• Twist the coil boot slightly, then pull the coil straight up and out.
• Repeat for all 4 coils.
• Tip: Lay coils in order to track any issues.

Step 3: Clean the spark plug wells

• Blow out each plug well using compressed air blow gun.
• This helps prevent dirt from falling into the cylinder when the plug comes out.

Step 4: Remove the old spark plugs

• Install a 5/8" spark plug socket on a 3/8" drive extension and 3/8" drive ratchet.
• Turn counterclockwise to loosen and remove the spark plug.
• Remove all 4 plugs the same way.

Step 5: Check the gap on the new plugs

• Use a feeler gauge set to verify the gap is within spec: 1.0–1.1 mm (0.039–0.043 in).
• If they are iridium-style, they are usually pre-gapped—avoid bending the tiny center electrode.

Step 6: Install the new spark plugs (start by hand)

• Place a new plug into the 5/8" spark plug socket (most sockets hold it with a rubber insert).
• Lower it into the plug well using the extension.
• Thread the plug by hand using only the extension (no ratchet at first) until it seats smoothly.
• If it doesn’t thread easily, back it out and try again—this avoids cross-threading.

Step 7: Torque the spark plugs

• Use a torque wrench (3/8" drive) (a torque wrench clicks when you hit the set tightness) with the 5/8" spark plug socket.
• Tighten each plug to Torque to 18–22 Nm (13–16 ft-lbs).
• Tighten smoothly—do not “reef” on it past the click.

Step 8: Reinstall the ignition coils

• Put a very small dab of dielectric grease inside each coil boot (the rubber part that touches the plug).
• Push the coil straight down until it fully seats on the plug.
• Install the coil bolt using a 10mm socket.
• Tighten coil bolts to Torque to 9–11 Nm (80–97 in-lbs).
• Reconnect each electrical connector until it clicks.

Step 9: Reinstall the engine cover

• Align the cover over the mounting points and press down firmly to snap it into the grommets.
• If you disconnected the battery, reconnect it (negative terminal last) using a 10mm wrench.

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✅ After Repair

• Start the engine and let it idle for 30–60 seconds. It should run smooth with no shaking.
• Listen for any ticking or air-leak sounds near the top of the engine (a loose coil connector can cause a misfire).
• Take a short test drive and confirm no check-engine light comes on.
• If a check-engine light appears or it runs rough, recheck coil connectors and coil seating first.

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💰 DIY vs Shop Cost

Shop Cost: $200-$450 (parts + labor)

DIY Cost: $40-$120 (parts only)

You Save: $160-$330 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.0-1.5 hours.

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