🔧 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 over time.

Difficulty Level: Intermediate | Estimated Time: 1.0-1.5 hours

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⚠️ Safety & Precautions

• ⚠️ Work on a fully cool engine to avoid burns and prevent thread damage in the aluminum cylinder head.
• ⚠️ Keep dirt out of the spark plug holes; debris can fall into the cylinder and cause engine damage.
• ⚠️ If you disconnect the battery, you may lose radio presets; 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:

• 10mm socket
• 3/8" ratchet
• 3/8" extension set (3" and 6")
• 16mm spark plug socket (rubber insert or magnet)
• 3/8" torque wrench (10-30 ft-lbs range)
• Compressed air blow gun
• Feeler gauge set (metric)
• Small flat trim tool
• Dielectric grease
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs (OEM-type iridium) - Qty: 4
• Ignition coil boot (if torn or oil-soaked) - Qty: 1-4

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📋 Before You Begin

• Park on level ground, shift to Park, and let the engine cool completely.
• Open the hood and remove any loose items around the top of the engine.
• If you plan to disconnect the battery: use a 10mm socket to remove the negative terminal and isolate it so it can’t spring back.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover

• Grip the cover and pull straight up to pop it off the rubber grommets.
• If it feels stuck, gently pry at the corners with a small flat trim tool.

Step 2: Unplug and remove the ignition coils

• Locate the 4 ignition coils on top of the engine (one per cylinder).
• Press the connector lock tab and unplug each coil connector by hand; use a small flat trim tool only if needed. Don’t yank the wires.
• Remove each coil hold-down bolt with a 10mm socket and 3/8" ratchet.
• Pull the coil straight up to remove it. (An “ignition coil” is the part that makes the high-voltage spark.)

Step 3: Clean around the spark plug wells

• Put on safety glasses.
• Blow out each spark plug tube with a compressed air blow gun to remove sand/dust.

Step 4: Remove the old spark plugs

• Insert the 16mm spark plug socket with a 3/8" extension down into the tube until it seats on the plug.
• Use a 3/8" ratchet to loosen and remove the plug, then lift it out with the socket.
• Repeat for all 4 cylinders.

Step 5: Check the new plug gap (only if needed)

• Most OEM-type iridium plugs come pre-gapped; still, verify with a feeler gauge set (metric).
• For your Tucson, the typical gap spec is around 1.0-1.1 mm; if your plugs include a spec card, follow that.
• Do not bend the iridium tip.

Step 6: Install the new spark plugs

• Start each plug by hand using the 16mm spark plug socket and extension only (no ratchet at first) to avoid cross-threading.
• Once hand-snug, tighten with a 3/8" torque wrench to Torque to 18-22 Nm (13-16 ft-lbs).
• No anti-seize on plated plugs.

Step 7: Reinstall coils and connectors

• Apply a small dab of dielectric grease inside each coil boot (dielectric grease is a non-conductive silicone grease that helps prevent moisture and sticking).
• Push each coil straight down until fully seated on the plug.
• Install the coil hold-down bolts using a 10mm socket, then tighten to Torque to 9-11 Nm (80-97 in-lbs).
• Reconnect each coil electrical connector until it clicks.

Step 8: Reinstall the engine cover

• Line up the cover with the grommets and press down firmly until it snaps in place.

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✅ After Repair

• Start your Tucson and let it idle for 30-60 seconds; it should run smooth with no shaking.
• If the check engine light was on for a misfire, it may take a few drive cycles to clear; a scan tool can clear it immediately.
• Take a short test drive and confirm there’s no hesitation under light acceleration.
• If you notice a “ticking” or exhaust smell, recheck plug torque and coil connectors.

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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 1.0-1.5 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.