🔧 Accent - Spark Plug Replacement

You’ll be removing the ignition coils on top of the engine, then swapping the 4 spark plugs underneath them. Fresh spark plugs help cold starts, fuel economy, and prevent misfires (shaking/check-engine light).

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

Assumption: your Accent uses coil-on-plug ignition (one coil per plug), which is standard for this engine.

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⚠️ Safety & Precautions

• ⚠️ Work on a fully cool engine to avoid burns and to protect the aluminum cylinder head threads.
• ⚠️ Keep dirt out of the spark plug holes; debris can damage the engine.
• ⚠️ Do not pull on wiring—only on connectors (the plastic plugs).
• ⚠️ Battery disconnect is not required, but it’s safer: disconnect the negative terminal if you’re nervous around electrical connectors.

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🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Nitrile gloves
• 10mm socket
• 3/8" drive ratchet
• 3/8" drive extension set (3" and 6")
• 5/8" spark plug socket (rubber insert)
• Torque wrench (3/8" drive, 10-30 ft-lbs range)
• Small flat screwdriver
• Compressed air blow gun or canned air
• Feeler gauge set

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs (OEM-spec iridium/long-life) - Qty: 4
• Dielectric grease (silicone) - Qty: 1

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📋 Before You Begin

• Park on level ground, put the shifter in 1st gear, and set the parking brake.
• Open the hood and let the engine cool completely (at least 30-60 minutes).
• If disconnecting the battery: use a 10mm socket to remove the negative terminal and move it aside so it can’t spring back.
• Lay out the new spark plugs and keep them clean; don’t drop them.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Access the ignition coils

• If your Accent has a top plastic engine cover, remove it (usually it pulls up by hand). If it has fasteners, remove them with a 10mm socket.
• If an air intake snorkel/duct blocks access, loosen its clamps/bolts with a 10mm socket and move it aside.

Step 2: Unplug and unbolt the ignition coils

• On each coil, press the connector tab and unplug it. If the tab is stubborn, gently help it with a small flat screwdriver (don’t break the tab).
• Remove the coil hold-down bolt using a 10mm socket.
• Pull the coil straight up to remove it. Twist slightly, then pull up.

Step 3: Clean around each spark plug well

• Before removing the spark plug, blow out the spark plug hole using compressed air blow gun or canned air.
• This prevents dirt from falling into the cylinder (inside the engine).

Step 4: Remove the old spark plugs

• Install the 5/8" spark plug socket (rubber insert) onto a 3/8" drive extension and 3/8" drive ratchet.
• Turn counterclockwise to loosen, then remove the spark plug.
• Repeat for all 4 cylinders.

Step 5: Check the gap on the new spark plugs

• Use a feeler gauge set to verify the gap matches the plug manufacturer spec for your Accent.
• Many OEM-spec iridium plugs come pre-gapped; if it’s an iridium fine-tip plug, don’t bend the center electrode. When in doubt, don’t “re-gap” iridium.

Step 6: Install the new spark plugs by hand first

• Place a new plug into the 5/8" spark plug socket (rubber insert) so it holds the plug.
• Thread it into the engine by hand using only the 3/8" drive extension (no ratchet at first).
• If it doesn’t thread smoothly, back it out and try again—this helps prevent cross-threading (damaging the threads in the aluminum head).

Step 7: Torque the spark plugs

• Use a torque wrench (3/8" drive, 10-30 ft-lbs range) with the 5/8" spark plug socket (rubber insert).
• Torque to 20 Nm (15 ft-lbs).
• Repeat for all 4 spark plugs.

Step 8: Reinstall ignition coils

• Put a tiny dab of dielectric grease (silicone) inside each coil boot (the rubber part). This helps prevent moisture and makes future removal easier.
• Push each coil straight down until it fully seats on the spark plug.
• Install the coil hold-down bolt with a 10mm socket, then tighten with a torque wrench: Torque to 9 Nm (80 in-lbs).
• Plug the electrical connectors back in until they click.

Step 9: Reinstall any covers/ducting

• Reinstall the air intake duct/snorkel (if removed) using a 10mm socket.
• Reinstall the engine cover (if equipped).
• 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 with no shaking.
• If you get a check-engine light or a rough idle, shut it off and re-check that every coil connector is fully clicked in.
• Take a short test drive and confirm normal power and no warning lights.

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💰 DIY vs Shop Cost

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

DIY Cost: $35-$90 (parts only)

You Save: $145-$260 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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