🔧 Fusion - Spark Plug Replacement

On your Fusion 2.5L, the spark plugs sit on top of the engine under the ignition coils, so you can replace them without removing the intake manifold. New plugs help prevent misfires, rough idle, and poor fuel economy.

Difficulty Level: Beginner | Estimated Time: 0.8-1.5 hours

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⚠️ Safety & Precautions

• 🧯 Work on a completely cool engine to avoid burns and damaged threads.
• 🛑 Keep dirt out of the plug holes; debris can damage the engine.
• 🔌 Battery disconnect is not required, but keep the key off and don’t unplug/plug coils with the engine running.

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🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Nitrile gloves
• 3/8" drive ratchet
• 3/8" drive torque wrench (5-30 ft-lbs range)
• 8mm socket
• 6" 3/8" drive extension
• 16mm spark plug socket
• Small flathead screwdriver
• Compressed air or hand air blower
• Clean shop towels

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs (OEM-equivalent for 2.5L) - Qty: 4
• Dielectric grease - Qty: 1

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📋 Before You Begin

• 🅿️ Park on level ground, set the parking brake, and turn the ignition completely off.
• Let the engine cool fully (at least 30-60 minutes if it was recently running).
• Lay out tools so nothing falls into the engine bay.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover (if equipped)

• Pull the cover straight upward by hand to release the rubber grommets.
• Set it aside on a clean towel.

Step 2: Unplug and remove ignition coil #1

• Use a small flathead screwdriver to gently lift the connector lock tab, then pull the connector straight off.
• Use an 8mm socket with a 3/8" drive ratchet to remove the coil hold-down bolt.
• Twist the coil slightly, then pull it straight up to remove it. Gentle twist breaks the boot seal.
• Ignition coil: the pencil-shaped part sitting on top of each spark plug.

Step 3: Clean the spark plug well

• Blow out the area around the spark plug hole using compressed air or hand air blower.
• Wipe nearby dirt with clean shop towels.

Step 4: Remove the old spark plug

• Install the 16mm spark plug socket onto a 6" 3/8" drive extension and 3/8" drive ratchet.
• Turn counterclockwise to loosen and remove the plug.
• Lift it out carefully and set it aside.

Step 5: Install the new spark plug (start by hand)

• Place the new plug into the 16mm spark plug socket and lower it into the hole with the extension.
• Thread it in by hand using only the extension (no ratchet at first) until it seats. Hand-threading prevents cross-threading.
• Do not add anti-seize unless your plug manufacturer specifically says to; most modern plugs are plated.

Step 6: Torque the spark plug

• Use a 3/8" drive torque wrench with the 16mm spark plug socket to tighten the plug.
• Torque to 15 Nm (11 ft-lbs)

Step 7: Reinstall the ignition coil

• Apply a pea-sized amount of dielectric grease inside the coil boot (the rubber “tube” that seals to the plug).
• Push the coil straight down until fully seated.
• Install the hold-down bolt using an 8mm socket, then tighten with a 3/8" drive torque wrench.
• Torque to 8 Nm (71 in-lbs)
• Reconnect the coil electrical connector until it clicks.

Step 8: Repeat for the remaining cylinders

• Repeat Steps 2 through 7 for the other three coils/plugs, one cylinder at a time.
• One-at-a-time prevents mixing connectors.

Step 9: Reinstall the engine cover

• Align the cover, then press down firmly by hand to snap it onto the grommets.

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✅ After Repair

• Start the engine and let it idle for 30-60 seconds; it should run smooth with no shaking.
• If you notice a flashing check engine light, shut it off—one coil connector may not be fully seated.
• Take a short 5-10 minute test drive and recheck for any odd hesitation.

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💰 DIY vs Shop Cost

Shop Cost: $180-$350 (parts + labor)

DIY Cost: $35-$90 (parts only)

You Save: $145-$260 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.8-1.2 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.