🔧 Accord - Spark Plug Replacement

On your Accord, the spark plugs sit under the ignition coils on top of the engine. Replacing them restores smooth starts, power, and fuel economy, and helps prevent misfires.

Difficulty Level: Beginner | Estimated Time: 0.5-1.5 hours

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⚠️ Safety & Precautions

• ⚠️ Work on a fully cool engine to avoid burns and prevent damaging aluminum threads.
• ⚠️ Keep dirt out of the spark plug holes—debris falling in can damage the engine.
• ⚠️ Do not over-tighten spark plugs; over-torque can strip the cylinder head.
• 🔋 Battery disconnect is not required, but keep the key off and avoid pulling on wiring.

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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
• 5/8" spark plug socket
• Torque wrench (3/8" drive, 10-30 ft-lbs range)
• Small flathead screwdriver
• Compressed air blow gun
• Shop vacuum
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

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

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📋 Before You Begin

• Park on level ground, shift to Park, and set the parking brake.
• Let the engine cool completely (best: sit 1-2 hours).
• Lay out the new plugs and keep them clean; do not drop them.

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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 4 ignition coils on top of the engine.
• If anything is covering access, remove it using a 10mm socket and 3/8" drive ratchet.

Step 2: Unplug the first ignition coil

• Press the electrical connector tab and pull the connector straight off.
• If it’s stubborn, gently help the tab with a small flathead screwdriver (don’t pry hard).
• Do one coil at a time.

Step 3: Remove the ignition coil

• Remove the coil hold-down bolt using a 10mm socket and 3/8" drive ratchet.
• Pull the coil straight up and out (a small twist helps).
• Reinstall torque later: Torque to 12 Nm (9 ft-lbs).

Step 4: Clean around the spark plug tube

• Blow out the spark plug hole area using compressed air blow gun.
• If there’s loose dirt on top, use a shop vacuum first, then air.

Step 5: Remove the spark plug

• Install the 5/8" spark plug socket on a 3/8" drive extension and 3/8" drive ratchet.
• Turn counterclockwise to loosen, then spin it out carefully.
• If it feels extremely tight, stop and work it slowly to avoid thread damage.

Step 6: Install the new spark plug by hand first

• Put the new plug into the 5/8" spark plug socket and lower it into the hole.
• Thread it in by hand using only the extension (no ratchet) for several turns so it doesn’t cross-thread.
• If it won’t thread easily, back it out and restart.

Step 7: Torque the spark plug

• Set your torque wrench (a tool that “clicks” at the correct tightness) to 18 Nm (13 ft-lbs).
• Tighten the spark plug until the torque wrench clicks: Torque to 18 Nm (13 ft-lbs).
• Do not add extra tightening after the click.

Step 8: Reinstall the ignition coil

• Apply a tiny smear of dielectric grease (non-conductive silicone grease that helps prevent moisture sticking) inside the rubber boot of the coil.
• Push the coil straight down onto the spark plug until fully seated.
• Install the coil bolt using a 10mm socket and 3/8" drive ratchet, then: Torque to 12 Nm (9 ft-lbs) with the torque wrench.

Step 9: Reconnect the coil connector

• Push the connector on until it clicks.
• Gently tug to confirm it’s locked.

Step 10: Repeat for the remaining 3 cylinders

• Repeat Steps 2-9 for each coil/spark plug, one at a time.

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✅ After Repair

• Double-check all 4 coil connectors are fully clicked in.
• Start the engine and let it idle for 30-60 seconds; it should run smooth.
• If the check engine light comes on or it runs rough, shut it off and recheck coil connectors and coil seating.
• Take a short test drive and confirm normal acceleration and no warning lights.

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💰 DIY vs Shop Cost

Shop Cost: $220-$420 (parts + labor)

DIY Cost: $40-$120 (parts only)

You Save: $180-$300 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.7-1.2 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.