🔧 Accord - Spark Plug Replacement

Replacing the spark plugs on your Accord helps restore smooth idle, clean acceleration, and good fuel economy. This 1.5L turbo engine uses ignition coils on top of each spark plug, so you’ll remove the coils first, then replace the plugs one at a time.

Difficulty Level: Beginner | Estimated Time: 45 minutes-1.5 hours

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⚠️ Safety & Precautions

• ⚠️ Let the engine cool completely before starting; spark plugs thread into the aluminum cylinder head and hot threads can be damaged.
• ⚠️ Disconnect the negative battery cable to reduce the chance of accidental electrical shorts.
• ⚠️ Keep dirt out of the spark plug wells. Dirt can fall into the engine when a plug is removed.
• ⚠️ Do not use anti-seize on modern plated spark plug threads unless the plug maker specifically says to. It can cause over-tightening.
• ⚠️ Replace plugs carefully. Cross-threading means the plug starts crooked and can damage the cylinder head.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• Ratchet wrench 3/8-inch drive
• 6-inch extension 3/8-inch drive
• 5/8-inch spark plug socket 3/8-inch drive
• Torque wrench 3/8-inch drive
• Spark plug gap gauge
• Compressed air can or blow gun
• Needle-nose pliers
• Dielectric grease
• Clean shop towels
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Iridium spark plugs - Qty: 4

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📋 Before You Begin

• Park your Accord on level ground, shift to Park, and set the parking brake.
• Open the hood and let the engine cool until it is comfortable to touch.
• Use a 10mm socket to loosen the negative battery terminal, then move the cable aside so it cannot spring back onto the battery post.
• A spark plug socket is a deep socket with a rubber insert or magnet that holds the spark plug straight while removing and installing it.
• Dielectric grease is an electrical-safe silicone grease used lightly inside the ignition coil boot to help prevent moisture and sticking.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the Engine Cover

• Use both hands to lift the plastic engine cover straight upward.
• The cover is held by rubber grommets, so it may pop loose suddenly.
• Set the cover aside on a clean surface.
• Lift evenly to avoid cracking tabs.

Step 2: Locate the Ignition Coils

• Look across the top of the engine for four ignition coils.
• Each ignition coil sits directly above one spark plug.
• An ignition coil is the small electrical part that sends high voltage to the spark plug.

Step 3: Unplug the First Ignition Coil Connector

• Start with one cylinder only. This helps prevent mixing parts or leaving a plug loose.
• Use your fingers to press the connector lock tab, then pull the connector straight back.
• If the connector is stubborn, use needle-nose pliers gently on the connector body, not the wires.
• Never pull on the wires.

Step 4: Remove the Ignition Coil Bolt

• Use a 10mm socket and ratchet wrench to remove the ignition coil retaining bolt.
• Place the bolt somewhere safe.
• Gently twist the ignition coil by hand to break the rubber boot loose.

Step 5: Remove the Ignition Coil

• Pull the ignition coil straight up by hand.
• If it feels stuck, twist it slightly while pulling upward.
• Set the coil down in the same position it came from.

Step 6: Clean the Spark Plug Well

• Use compressed air can or blow gun to blow dirt away from the spark plug well.
• Wear safety glasses while doing this.
• Wipe around the opening with a clean shop towel.
• Clean first, then remove the plug.

Step 7: Remove the Old Spark Plug

• Install the 5/8-inch spark plug socket onto the 6-inch extension and ratchet wrench.
• Lower the socket straight down onto the spark plug.
• Turn counterclockwise slowly to loosen the plug.
• Once loose, spin it out gently with the extension by hand.
• Lift the old spark plug out using the spark plug socket.

Step 8: Check the New Spark Plug

• Use a spark plug gap gauge to verify the gap is correct before installation.
• The gap is the small space between the center tip and the curved ground strap.
• For your Accord, use iridium spark plugs matched for the 1.5L turbo engine.
• Do not force-adjust fine-wire iridium plugs unless the plug manufacturer allows it.

Step 9: Install the New Spark Plug by Hand

• Place the new spark plug into the 5/8-inch spark plug socket.
• Use the 6-inch extension only, without the ratchet wrench, to start threading the plug by hand.
• Turn clockwise slowly until the plug seats lightly.
• If it feels tight right away, stop, back it out, and start again straight.
• Hand-starting prevents cross-threading.

Step 10: Torque the New Spark Plug

• Attach the torque wrench 3/8-inch drive to the 6-inch extension and 5/8-inch spark plug socket.
• Tighten the spark plug to Torque to 18 Nm (13 ft-lbs).
• Do not over-tighten. The cylinder head is aluminum and can be damaged.

Step 11: Reinstall the Ignition Coil

• Apply a tiny amount of dielectric grease inside the end of the ignition coil boot.
• Push the ignition coil straight down over the new spark plug until it seats fully.
• Use the 10mm socket and torque wrench to install the coil bolt.
• Tighten the ignition coil bolt to Torque to 12 Nm (9 ft-lbs).

Step 12: Reconnect the Ignition Coil Connector

• Push the electrical connector onto the ignition coil until it clicks.
• Gently tug the connector by hand to confirm it is locked.

Step 13: Repeat for the Other Three Spark Plugs

• Repeat Steps 3 through 12 for the remaining three cylinders.
• Use the same 10mm socket, ratchet wrench, 6-inch extension, 5/8-inch spark plug socket, and torque wrench.
• Work one plug at a time so each ignition coil goes back where it came from.

Step 14: Reinstall the Engine Cover

• Line up the plastic engine cover with its mounting grommets.
• Press down firmly by hand until it snaps into place.

Step 15: Reconnect the Battery

• Place the negative battery cable back onto the battery post.
• Use a 10mm socket to tighten the terminal nut snugly.
• Do not over-tighten the battery terminal.

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✅ After Repair

• Start your Accord and let it idle for 1-2 minutes.
• The idle may briefly relearn after the battery was disconnected.
• Listen for smooth running. A rough idle usually means a coil connector is not fully clicked in.
• Check that the check engine light is off.
• Take a short test drive and confirm smooth acceleration with no misfire or hesitation.
• If the radio, clock, or auto window function needs reset after battery disconnect, restore those settings through the normal controls.

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💰 DIY vs Shop Cost

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

DIY Cost: $45-$120 (parts only)

You Save: $175-$300 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.8-1.3 hours.

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🎯 Ready to get started?

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