🔧 Tucson - Spark Plug Replacement

On your Tucson, the spark plugs sit under the ignition coils on top of the engine. Replacing them restores smooth starting, power, and fuel economy, and helps prevent misfires as the plugs wear.

Difficulty Level: Intermediate | Estimated Time: 0.8-1.5 hours

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⚠️ Safety & Precautions

• ⚠️ Work on a cold engine to avoid burns and thread damage.
• ⚠️ Keep dirt out of the spark plug holes—debris can damage the engine.
• ⚠️ Do not pull on wiring; release the connector lock before unplugging.
• ⚠️ If you disconnect the battery, use a 10mm wrench and remove the negative (-) terminal first.

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🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Nitrile gloves
• 1/4" drive ratchet
• 3/8" drive ratchet
• 3/8" torque wrench (10-40 Nm range)
• 10mm socket
• 6" extension (3/8" drive)
• 5/8" (16mm) spark plug socket (rubber insert)
• Trim clip tool
• Compressed air blow gun
• Clean shop towels
• Dielectric grease

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs (OE-type iridium) - Qty: 4
• Ignition coil boots (optional, if torn/oil-soaked) - Qty: 4

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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 30-60 minutes after driving).
• Blow off loose dirt around the top of the engine using a compressed air blow gun.
• If you’re nervous about electrical connectors, disconnect the negative (-) battery terminal with a 10mm socket.

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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 evenly; if it uses clips, help it gently with a trim clip tool.
• Set the cover aside on a clean towel.

Step 2: Unplug one ignition coil

• Work one cylinder at a time so nothing gets mixed up.
• Press the connector lock and unplug the coil electrical connector by hand.
• If stuck, wiggle—don’t yank wires.

Step 3: Remove the ignition coil

• Remove the coil hold-down bolt using a 10mm socket and 1/4" drive ratchet.
• Twist the coil slightly, then pull straight up to remove it.
• Inspect the coil boot for oil, tears, or heavy corrosion.

Step 4: Clean the spark plug well

• Blow out the spark plug tube using a compressed air blow gun.
• Wipe the area with clean shop towels so dirt can’t fall in.

Step 5: Remove the old spark plug

• Install a 5/8" (16mm) spark plug socket (rubber insert) on a 6" extension (3/8" drive) and use a 3/8" drive ratchet to loosen the plug.
• Turn it out slowly and lift it out with the socket.
• If it feels extremely tight, stop and re-check that the engine is fully cool.

Step 6: Install the new spark plug (by hand first)

• Compare the new plug to the old one (same length and thread size).
• Do not adjust the gap on iridium plugs; they are set from the factory.
• Thread the new plug in by hand using the spark plug socket and extension only (no ratchet) until fully seated.
• Hand-threading prevents cross-threading.

Step 7: Torque the spark plug

• Set your 3/8" torque wrench (10-40 Nm range) and tighten the spark plug.
• Torque to 20 Nm (15 ft-lbs).

Step 8: Reinstall the ignition coil

• Apply a tiny amount of dielectric grease inside the coil boot (this helps moisture protection and future removal).
• Push the coil straight down until fully seated on the plug.
• Install the coil hold-down bolt using a 10mm socket.
• Torque to 9 Nm (80 in-lbs).
• Reconnect the coil electrical connector until it clicks.

Step 9: Repeat for the remaining cylinders

• Repeat Steps 2–8 for each coil/plug, one at a time.
• Keep everything clean and do not drop anything into the plug tubes.

Step 10: Reinstall the engine cover

• Press the cover straight down until all mounting points snap in.
• If you disconnected the battery, reconnect the negative (-) terminal using a 10mm socket.

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✅ After Repair

• Start the engine and let it idle for 30-60 seconds; it should run smooth.
• Listen for a ticking sound (could indicate a loose plug or coil not seated).
• If the check engine light is on or it runs rough, re-check each coil connector is fully clicked in.
• Test drive 5-10 minutes and re-check for any warning lights.

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💰 DIY vs Shop Cost

Shop Cost: $220-$450 (parts + labor)

DIY Cost: $45-$110 (parts only)

You Save: $175-$340 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.8-1.5 hours.

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🎯 Ready to get started?

HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.