🔧 Accord - Spark Plug Replacement

Replacing the spark plugs helps your A4—sorry—your Accord start easier, idle smoother, and maintain good fuel economy. On your Accord’s 2.4L engine, the plugs sit under the ignition coils on top of the engine, so access is straightforward once a few parts are moved.

Difficulty Level: Beginner | Estimated Time: 1-2 hours

Assumption: stock 2.4L coil-on-plug ignition.

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⚠️ Safety & Precautions

• ⚠️ Work on a cold engine to avoid burns and damaged threads.
• ⚠️ Keep dirt out of the spark plug holes; contamination can damage the engine.
• ⚠️ If you disconnect the battery, use a 10mm wrench and remove the negative terminal first.
• ⚠️ Do not over-tighten spark plugs; stripped threads are an expensive repair.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 1/4" drive ratchet
• 3/8" drive ratchet
• 3/8" drive extension set (3", 6")
• 5/8" spark plug socket
• Torque wrench (3/8" drive, 10-30 ft-lbs range)
• Small flat trim tool
• Compressed air or air blower
• Pick tool
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs (iridium, OEM-equivalent) - Qty: 4
• Dielectric grease - Qty: 1

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📋 Before You Begin

• Park on level ground, engine OFF, key out of the car.
• Let the engine cool fully (at least 1 hour if it was driven).
• Put on safety glasses—you’ll be blowing debris away from the plug wells.
• Know your tool: a torque wrench is a measuring ratchet that tightens to an exact setting.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Open access to the ignition coils

• Open the hood and locate the ignition coils on top of the engine (4 coils in a row).
• If a plastic engine cover is present, remove it by hand or use a small flat trim tool as needed to release clips.

Step 2: Unplug the ignition coil connectors

• Use a pick tool to gently lift the connector lock tab if needed, then unplug each coil connector.
• Don’t pull on the wires. Pull on the connector body.

Step 3: Remove the ignition coils

• Use a 10mm socket with a 1/4" drive ratchet to remove the 10mm bolt holding each coil.
• Twist each coil slightly, then pull straight up to remove it.

Step 4: Clean the spark plug wells

• Use compressed air or air blower to blow out dirt from each spark plug hole before removing the plug.
• This prevents grit from falling into the cylinder.

Step 5: Remove the old spark plugs

• Install the 5/8" spark plug socket on a 3/8" drive extension and 3/8" drive ratchet.
• Lower the socket straight into the spark plug hole and loosen the plug counterclockwise.
• Lift the plug out with the socket.

Step 6: Install the new spark plugs (hand-thread first)

• Start each new plug by hand using the 5/8" spark plug socket and extension only (no ratchet at first).
• Turn clockwise by hand until it seats smoothly.
• If it doesn’t turn easily, back out and retry.
• Do not apply anti-seize to the plug threads (Honda-style plated plugs are designed to go in dry).

Step 7: Torque the spark plugs

• Use a torque wrench (3/8" drive) with the 5/8" spark plug socket to tighten each plug.
• Torque to 18 Nm (13 ft-lbs)

Step 8: Reinstall ignition coils

• Apply a tiny smear of dielectric grease inside each coil boot (it helps prevent moisture and makes future removal easier).
• Push each coil straight down until fully seated on the plug.
• Reinstall each coil bolt using a 10mm socket and 1/4" drive ratchet.
• Torque to 12 Nm (9 ft-lbs)

Step 9: Reconnect electrical connectors and recheck your work

• Plug in each coil connector until it clicks.
• Do a final look: no loose tools, all 4 connectors seated, all 4 bolts installed.
• Reinstall the engine cover (if equipped) by hand.

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✅ After Repair

• Start the engine and let it idle for 1-2 minutes. It should run smooth with no flashing check engine light.
• If the engine runs rough, shut it off and recheck coil connectors and coil seating.
• Take a short test drive and confirm normal power and smooth acceleration.

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💰 DIY vs Shop Cost

Shop Cost: $200-$350 (parts + labor)

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

You Save: $160-$260 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.