🔧 Fusion - Spark Plug Replacement

Replacing the spark plugs on your Fusion helps restore smooth idle, easier starting, and proper fuel economy. The 2.5L inline-4 has four spark plugs located under the ignition coils on top of the engine.

Difficulty Level: Beginner | Estimated Time: 45-90 minutes

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⚠️ Safety & Precautions

• ⚠️ Let the engine cool completely before starting. Spark plugs thread into aluminum cylinder head material, which is easier to damage when hot.
• ⚠️ Disconnect the negative battery cable to prevent accidental ignition coil activation.
• ⚠️ Do not drop dirt into the spark plug wells. A spark plug well is the deep tube where each plug sits.
• ⚠️ Start new spark plugs by hand first. Cross-threading means the plug goes in crooked and can damage the cylinder head.

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🔧 Required Tools

You'll need the following tools for this repair:

• 8mm socket
• 10mm socket
• 3/8-inch ratchet
• 3/8-inch extension 6-inch
• 5/8-inch spark plug socket
• Torque wrench 5-80 ft-lbs
• Spark plug gap gauge
• Compressed air blow gun
• Dielectric grease
• Anti-seize compound
• Needle-nose pliers
• Shop towels
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs - Qty: 4
• Ignition coil boots - Qty: 4

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📋 Before You Begin

• 🅿️ Park your Fusion on level ground, shift to Park, and set the parking brake.
• ❄️ Let the engine cool until it is comfortable to touch.
• 🔋 Use a 10mm socket to disconnect the negative battery cable. Move the cable aside so it cannot touch the battery post.
• 🧼 Blow dirt away from the top of the engine before removing ignition coils.
• 📏 Check the new spark plug gap before installation. Use the plug specification printed on the under-hood emissions label or the plug maker’s listing for your Fusion.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the Engine Cover Area Obstructions

• Use your hands to remove any loose plastic engine appearance cover if equipped.
• Use a 10mm socket and 3/8-inch ratchet to loosen the intake tube clamp if the tube blocks access.
• Use needle-nose pliers to release any small hose clamp gently if a hose needs to move aside.
• Take a photo before unplugging anything.

Step 2: Disconnect the Ignition Coil Connectors

• Use your fingers to press the locking tab on each ignition coil electrical connector.
• Pull the connector straight back. Do not pull on the wires.
• If a connector is tight, use needle-nose pliers gently on the connector body only.
• An ignition coil is the small electrical unit that sits above each spark plug and sends spark energy to it.

Step 3: Remove the Ignition Coils

• Use an 8mm socket, 3/8-inch extension, and 3/8-inch ratchet to remove the ignition coil retaining bolt from each coil.
• Pull each ignition coil straight up with a slight twist.
• Set the coils in order from left to right so they go back into the same locations.
• Inspect each rubber coil boot for cracks, swelling, oil contamination, or carbon tracking. Carbon tracking looks like a thin black lightning mark.

Step 4: Clean the Spark Plug Wells

• Put on safety glasses.
• Use a compressed air blow gun to blow dirt out of each spark plug well before removing the plugs.
• Use shop towels around the area to catch loose debris.
• Clean first. Remove plugs second.

Step 5: Remove the Old Spark Plugs

• Use a 5/8-inch spark plug socket, 6-inch extension, and 3/8-inch ratchet to loosen each spark plug counterclockwise.
• Once loose, turn slowly until the plug comes out.
• Remove one spark plug at a time to avoid mixing anything up.
• If a plug feels stuck, stop and tighten it slightly, then loosen again slowly. Do not force it.

Step 6: Check and Prepare the New Spark Plugs

• Use a spark plug gap gauge to verify each new plug gap matches the specification for your Fusion.
• Do not pry against fine-wire iridium or platinum center electrodes. They can be damaged easily.
• Apply a very small amount of anti-seize compound only if the spark plug manufacturer allows it. Many modern coated plugs are installed dry.
• Apply a small amount of dielectric grease inside each ignition coil boot. Dielectric grease is non-conductive grease that helps seal moisture out of the boot.

Step 7: Install the New Spark Plugs

• Place one new spark plug into the 5/8-inch spark plug socket.
• Use only the 6-inch extension by hand to start the spark plug into the cylinder head.
• Turn clockwise by hand for several turns. It should spin smoothly.
• Use a torque wrench with the 5/8-inch spark plug socket to tighten each spark plug to Torque to 15 Nm (11 ft-lbs).
• Hand-starting prevents expensive thread damage.

Step 8: Reinstall the Ignition Coils

• Push each ignition coil straight down onto its spark plug until it seats fully.
• Use an 8mm socket, 6-inch extension, and torque wrench to install each ignition coil retaining bolt.
• Tighten each ignition coil bolt to Torque to 6 Nm (53 in-lbs).
• Reconnect each ignition coil electrical connector until the locking tab clicks.

Step 9: Reinstall Removed Intake Parts

• Use your hands to reinstall any plastic cover removed earlier.
• Use a 10mm socket and 3/8-inch ratchet to tighten the intake tube clamp if it was loosened.
• Reconnect any hose you moved and confirm it is fully seated.

Step 10: Reconnect the Battery

• Use a 10mm socket to reconnect the negative battery cable.
• Tighten the battery terminal snugly. Do not overtighten.
• Make sure no tools are left in the engine bay.

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✅ After Repair

• ✅ Start your Fusion and let it idle for 1-2 minutes.
• ✅ Listen for smooth idle and check that the engine does not shake or stumble.
• ✅ If the check engine light flashes or the engine misfires, turn it off and recheck every ignition coil connector.
• ✅ Take a short test drive. Acceleration should feel smooth.
• ✅ After the drive, recheck that the intake tube and connectors are secure.

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💰 DIY vs Shop Cost

Shop Cost: $180-$320 parts + labor

DIY Cost: $35-$100 parts only

You Save: $145-$220 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.7-1.0 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.