🔧 Fusion - Spark Plug Replacement

Replacing the spark plugs on your Fusion helps restore smooth starting, clean idle, fuel economy, and proper hybrid engine operation when the gasoline engine runs. The 2.0L plug-in hybrid engine uses four spark plugs located under the ignition coils on top of the engine.

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

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⚠️ Safety & Precautions

• ⚠️ Work only with the vehicle OFF, in Park, and on a cool engine to avoid burns and thread damage.
• ⚠️ This is a plug-in hybrid, but spark plug service is on the gasoline engine only. Do not touch orange high-voltage cables or high-voltage components.
• ⚠️ Keep the key fob away from the vehicle while working so the engine cannot start automatically.
• ⚠️ Disconnect the 12-volt negative battery cable before unplugging ignition coils.
• ⚠️ Do not remove spark plugs if dirt or debris is sitting around the plug wells. Dirt can fall into the engine.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 8mm socket
• 3/8-inch ratchet
• 3/8-inch extension 6-inch
• 5/8-inch spark plug socket
• Torque wrench 3/8-inch drive
• Flathead screwdriver small
• Compressed air blow gun
• Spark plug gap gauge
• Needle-nose pliers
• Dielectric grease packet
• 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
• Ignition coil boots - Qty: 4
• Dielectric grease - Qty: 1

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📋 Before You Begin

• Park your Fusion on level ground and press the Start/Stop button once to turn the vehicle fully OFF.
• Remove the key fob from the vehicle and keep it at least 15 feet away.
• Let the gasoline engine cool completely before removing spark plugs.
• Open the hood and use safety glasses before blowing debris away from the plug wells.
• A spark plug socket is a deep socket with a rubber insert or magnet that holds the spark plug while you lift it out.
• A torque wrench tightens bolts to a measured amount so small engine threads are not damaged.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Power Down and Disconnect the 12-Volt Battery

• Use a 10mm socket and 3/8-inch ratchet to loosen the negative 12-volt battery cable clamp.
• Remove the negative cable from the battery post and position it so it cannot spring back and touch the post.
• Negative cable is usually black.

Step 2: Remove the Engine Appearance Cover

• Grip the plastic engine cover with both hands and pull straight upward to release it from its rubber mounts.
• No tool is normally needed for the cover.
• Set the cover aside where it will not get scratched or stepped on.

Step 3: Clean Around the Ignition Coils

• Put on safety glasses.
• Use the compressed air blow gun to blow dirt and grit away from the top of the engine and around each ignition coil.
• Ignition coils are the four small electrical units sitting directly above the spark plugs.
• Clean first. Engines hate dirt.

Step 4: Unplug the Ignition Coil Connectors

• Use a small flathead screwdriver only if needed to gently release each connector lock tab.
• Pull each connector straight back by the plastic connector body, not by the wires.
• If a connector is stubborn, use needle-nose pliers gently on the connector body.

Step 5: Remove the Ignition Coils

• Use an 8mm socket, 3/8-inch extension 6-inch, and 3/8-inch ratchet to remove the ignition coil retaining bolts.
• Twist each ignition coil slightly by hand, then pull it straight upward out of the spark plug well.
• Place the coils in order from left to right so each one goes back into the same cylinder.
• When reinstalling later, tighten each ignition coil bolt to Torque to 6 Nm (53 in-lbs).

Step 6: Remove the Old Spark Plugs

• Use the 5/8-inch spark plug socket, 3/8-inch extension 6-inch, and 3/8-inch ratchet to loosen the first spark plug counterclockwise.
• Once loose, turn slowly and lift the plug out carefully with the spark plug socket.
• Repeat for the remaining three spark plugs.
• If a plug feels stuck, stop and tighten it slightly, then loosen again slowly.
• Do not force a stuck plug.

Step 7: Check the New Spark Plugs

• Use a spark plug gap gauge to verify the electrode gap is about 0.051 inch (1.3 mm).
• Do not pry hard on iridium spark plug tips. Iridium tips are delicate and can be damaged easily.
• Confirm the new plugs match the removed plugs in thread length and seat style before installation.

Step 8: Install the New Spark Plugs by Hand First

• Place one new spark plug into the 5/8-inch spark plug socket.
• Use the 3/8-inch extension 6-inch by hand only to start threading the spark plug clockwise.
• Turn it several full turns by hand before using a ratchet. This helps prevent cross-threading, which means the plug is going in crooked and can damage the cylinder head.
• Repeat for all four spark plugs.

Step 9: Torque the New Spark Plugs

• Attach the torque wrench 3/8-inch drive to the 5/8-inch spark plug socket and 3/8-inch extension 6-inch.
• Tighten each spark plug to Torque to 15 Nm (11 ft-lbs).
• Do not add anti-seize unless the spark plug manufacturer specifically requires it.
• Overtightening can damage aluminum threads.

Step 10: Inspect and Grease the Coil Boots

• Inspect each ignition coil boot for cracks, oil swelling, or carbon tracking, which looks like a thin black lightning mark.
• Replace the boots if worn or cracked.
• Apply a small amount of dielectric grease packet inside the end of each boot. Dielectric grease helps seal out moisture but does not conduct electricity.

Step 11: Reinstall the Ignition Coils

• Push each ignition coil straight down onto its spark plug until it seats fully.
• Use the 8mm socket, 3/8-inch extension 6-inch, and torque wrench 3/8-inch drive to tighten each coil bolt to Torque to 6 Nm (53 in-lbs).
• Reconnect each electrical connector until it clicks.

Step 12: Reinstall the Engine Cover and Battery Cable

• Press the engine cover straight down onto its rubber mounts by hand.
• Reconnect the negative 12-volt battery cable.
• Use a 10mm socket and 3/8-inch ratchet to snug the clamp. Do not overtighten it.

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✅ After Repair

• Start your Fusion and let the gasoline engine run if it starts automatically.
• If the vehicle stays in electric mode, select a drive mode or condition that starts the gasoline engine, then listen for smooth idle.
• Check that there are no warning lights, rough running, ticking from loose plugs, or misfire shaking.
• Take a short, gentle test drive and confirm smooth acceleration when the gasoline engine comes on.
• The clock, radio presets, and one-touch window function may need resetting after the 12-volt battery disconnect.

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💰 DIY vs Shop Cost

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

DIY Cost: $45-$110 (parts only)

You Save: $175-$270 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1-1.5 hours.

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🎯 Ready to get started?

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