🔧 Accord - Spark Plug Replacement

On your Accord, the spark plugs sit under the ignition coils on top of the engine. Replacing them restores smooth starting, idle quality, and fuel economy—especially if the plugs are worn or you have a misfire.

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

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⚠️ Safety & Precautions

• 🧯 Let the engine cool fully; the aluminum cylinder head is easy to damage when hot.
• 🧤 Keep dirt out of the plug holes; debris can fall into the cylinder.
• ⚡ 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
• Ratchet
• 10mm socket
• 3/8" drive torque wrench (5-80 ft-lbs range)
• 5/8" spark plug socket (3/8" drive)
• 6" socket extension (3/8" drive)
• Small flathead screwdriver
• Compressed air blow gun
• Shop vacuum with small nozzle
• Magnetic pickup tool
• Feeler gauge set (wire type)

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs (iridium, correct fit for Accord 2.4L) - Qty: 4
• Dielectric grease packet - Qty: 1

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📋 Before You Begin

• Park on level ground, shift to Park, and set the parking brake.
• Open the hood and let the engine cool for at least 30 minutes.
• Optional (safer for beginners): disconnect the battery negative cable using a 10mm wrench.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Access the ignition coils

• If your Accord has a small top cover, remove the fasteners using a 10mm socket, then lift it off.
• You’ll see 4 ignition coils in a row on top of the engine.

Step 2: Unplug the coil connectors

• Press the connector tab and pull the plug straight off each ignition coil.
• If a tab is stubborn, gently help it with a small flathead screwdriver (don’t pry hard).

Step 3: Remove the ignition coils

• Remove each coil hold-down bolt using a 10mm socket.
• Pull the coil straight up and out.
• Wiggle gently; don’t yank the wiring.
• When reinstalling later: Torque to 12 Nm (9 ft-lbs).

Step 4: Clean the plug wells (very important)

• Use a shop vacuum with small nozzle to remove loose dust around each plug hole.
• Then use compressed air blow gun to blow out the spark plug tube.
• This prevents grit from falling into the cylinder when the plug comes out.

Step 5: Remove the old spark plugs

• Install the 5/8" spark plug socket on a 6" socket extension and ratchet.
• Turn counterclockwise to loosen, then remove the plug.
• If the plug drops or you can’t lift it out, use a magnetic pickup tool.

Step 6: Check the new plug gap (don’t adjust iridium tips)

• Use a feeler gauge set (wire type) to verify the gap matches the plug manufacturer spec.
• Do not bend or “re-gap” an iridium fine-wire tip; replace the plug if it’s damaged.

Step 7: Install the new spark plugs (hand-thread first)

• Place a new plug into the 5/8" spark plug socket.
• Lower it into the hole and turn it clockwise by hand using only the extension (no ratchet at first).
• If it doesn’t thread smoothly, back it out and try again (this avoids cross-threading).
• Final tighten with a 3/8" drive torque wrench: Torque to 18 Nm (13 ft-lbs).
• Do not use anti-seize on plated plugs.

Step 8: Reinstall coils and connectors

• Apply a tiny amount of dielectric grease inside each coil boot (the rubber tip). (Dielectric grease is a non-conductive grease that helps prevent moisture and sticking.)
• Push each ignition coil straight down onto the spark plug until fully seated.
• Install the coil bolts using a 10mm socket, then torque to 12 Nm (9 ft-lbs) using a torque wrench.
• Reconnect each coil electrical connector until it clicks.

Step 9: Reinstall any engine cover

• Reinstall the cover using a 10mm socket.

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✅ After Repair

• If you disconnected the battery, reconnect the negative terminal using a 10mm wrench.
• Start the engine and listen for a smooth idle (no shaking).
• If you get a flashing check engine light or the engine runs rough, stop and re-check that every coil connector is fully clicked in.

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💰 DIY vs Shop Cost

Shop Cost: $220-$380 (parts + labor)

DIY Cost: $45-$90 (parts only)

You Save: $130-$300 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.