🔧 Accord - Spark Plug Replacement

Your Accord uses four spark plugs to ignite the air/fuel mix. Replacing worn plugs helps prevent misfires, rough idle, and poor fuel economy, and it’s a straightforward job on the 2.4L since the plugs sit on top of the engine.

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

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⚠️ Safety & Precautions

• 🛑 Let the engine fully cool before starting; hot aluminum threads can strip.
• 🧯 Keep dirt out of the plug holes; debris can damage the engine.
• 🧤 Wear safety glasses and gloves when blowing out plug wells.
• 🔋 Battery disconnect is not required, but if you’re nervous about accidental shorts, remove the negative cable with a 10mm wrench.

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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 (3" and 6")
• 5/8" spark plug socket (rubber insert or magnet)
• Torque wrench (3/8" drive, 10-30 ft-lbs range)
• Small flathead screwdriver
• Compressed air blow gun
• Shop vacuum
• Feeler gauge (wire-style)
• Dielectric grease
• Nitrile gloves
• Safety glasses
• Fender cover

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Iridium spark plugs (OE type) - Qty: 4

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📋 Before You Begin

• 🅿️ Park on level ground, shut the engine off, and open the hood.
• ❄️ Wait until the valve cover area is cool to the touch.
• 🧼 If the top of the engine is dusty, use a shop vacuum to clean around the coils first.
• 🧠 A “spark plug well” is the deep tube the plug sits down inside; keeping it clean is important.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover (if equipped)

• Use a 10mm socket with a 3/8" drive ratchet to remove the engine cover fasteners.
• Lift the cover off and set it aside.

Step 2: Unplug and remove the ignition coils

• On each coil, press the connector tab to unplug it; if it’s stubborn, gently help the tab with a small flathead screwdriver. Don’t pry hard on the wires.
• Use a 10mm socket and 3/8" drive ratchet to remove the coil hold-down bolt.
• Twist the coil slightly, then pull it straight up and out.
• Repeat for all 4 coils.
• When reinstalling later: Torque to 12 Nm (9 ft-lbs)

Step 3: Clean out the spark plug wells

• Use a shop vacuum around each plug well opening.
• Use compressed air blow gun to blow straight down each well to remove grit and sand.
• Wear safety glasses for this step.

Step 4: Remove the old spark plugs

• Install the 5/8" spark plug socket onto a 3/8" drive extension and 3/8" drive ratchet.
• Lower the socket straight down onto the spark plug until fully seated.
• Break the plug loose, then spin it out the rest of the way.
• Lift the plug out using the spark plug socket.
• Repeat for all 4.

Step 5: Check the new spark plug gap (quick check only)

• Use a feeler gauge (wire-style) to verify the gap matches spec (typically around 1.0-1.1 mm (0.039-0.043 in)).
• If they’re iridium plugs, don’t bend the tiny center tip; if the gap is way off, exchange the plug instead of forcing it.

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

• Place a new plug into the 5/8" spark plug socket.
• Thread it in by hand first using only a 3/8" drive extension (no ratchet at first). This helps prevent cross-threading (starting the plug crooked).
• Once finger-tight, use a torque wrench to tighten: Torque to 18 Nm (13 ft-lbs)
• Do not use anti-seize on Honda iridium plugs.

Step 7: Reinstall coils and connectors

• Put a tiny dab of dielectric grease inside each coil boot (the rubber sleeve). Dielectric grease is a non-conductive silicone grease that helps keep moisture out.
• Push each coil straight down onto its spark plug until fully seated.
• Install the coil hold-down bolts using a 10mm socket, then finish with a torque wrench: Torque to 12 Nm (9 ft-lbs)
• Plug in each coil connector until it clicks.

Step 8: Reinstall the engine cover

• Reinstall the cover fasteners using a 10mm socket and 3/8" drive ratchet.

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✅ After Repair

• 🚗 Start the engine and let it idle for 30-60 seconds; it should run smooth.
• 🔎 If you get a flashing check engine light or a shaking idle, shut it off and re-check that every coil connector is fully clicked in.
• 🛣️ Take a short test drive and confirm normal acceleration with no hesitation.

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💰 DIY vs Shop Cost

Shop Cost: $250-$450 (parts + labor)

DIY Cost: $40-$90 (parts only)

You Save: $160-$410 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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