🔧 Fusion - Spark Plug Replacement

Replacing the spark plugs on your Fusion restores strong ignition, smooth idle, and good fuel economy. On the 2.5L engine, the plugs sit under the ignition coils on top of the engine, so this is a straightforward “remove-and-replace” job when the engine is cool.

Difficulty Level: Beginner | Estimated Time: 1.0-2.0 hours

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⚠️ Safety & Precautions

• ⚠️ Work on a fully cool engine to avoid burns and to protect aluminum threads in the cylinder head.
• ⚠️ Keep dirt out of the spark plug holes; debris can fall into the engine and cause damage.
• ⚠️ If you disconnect the battery: use a 10mm wrench to remove the negative terminal first, and reinstall it last.
• ⚠️ Do not over-tighten spark plugs; aluminum threads strip easily.

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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 (10-30 Nm range)
• 8mm socket
• 10mm socket
• 6" extension (3/8" drive)
• Spark plug socket 5/8" (16mm) with rubber insert
• Small flathead screwdriver
• Compressed air blow gun
• Feeler gauge set (inch)
• Magnetic pickup tool
• Flashlight

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs (OEM-equivalent, correct heat range) - 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 (at least 1 hour after driving).
• Open the hood and remove any loose items from the cowl area so nothing falls into the engine bay.
• Tip: Take a quick photo before unplugging anything.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover (if equipped)

• Use your hands to lift the cover straight up to release it from the rubber grommets.
• Set it aside where it won’t get stepped on.

Step 2: Unplug and remove ignition coils

• Each plug has an ignition coil on top (a “coil-on-plug” coil, meaning the coil sits directly over the spark plug).
• Use a small flathead screwdriver to gently release the electrical connector lock (do not pry hard).
• Pull the connector straight off the coil.
• Use an 8mm socket with a 3/8" drive ratchet to remove the coil hold-down bolt.
• Twist the coil slightly and pull it straight up to remove it.
• Repeat for all 4 coils.
• When reinstalling later: Torque to 8 Nm (71 in-lbs).

Step 3: Blow out the spark plug wells

• Use a compressed air blow gun to blow out each spark plug hole before removing the plugs.
• This prevents dirt from falling into the cylinder.

Step 4: Remove the old spark plugs

• Install the spark plug socket 5/8" (16mm) on a 6" extension (3/8" drive) and 3/8" drive ratchet.
• Turn counterclockwise to loosen, then remove the plug fully.
• If a plug feels unusually tight, stop and work it gently back and forth to avoid thread damage.
• Repeat for all 4 cylinders.

Step 5: Check and prep the new spark plugs

• Use a feeler gauge set (inch) to verify the plug gap matches spec for your engine family (many modern plugs come pre-gapped and should not be bent unless clearly off).
• Do not apply anti-seize unless the plug maker specifically instructs it; most modern plugs have plated threads.
• Apply a tiny amount of dielectric grease inside each coil boot (dielectric grease is a silicone grease that helps prevent moisture and makes future removal easier).

Step 6: Install the new spark plugs

• Place a new plug into the spark plug socket 5/8" (16mm) (the rubber insert helps hold it).
• Lower it into the hole using the 6" extension (3/8" drive).
• Thread the plug in by hand using only the extension (no ratchet yet) until it’s fully seated. This helps prevent cross-threading.
• Set your 3/8" drive torque wrench and tighten each plug to Torque to 15 Nm (11 ft-lbs).

Step 7: Reinstall coils and connectors

• Push each coil straight down until fully seated on the plug.
• Install the coil bolt using an 8mm socket.
• Tighten with a 3/8" drive torque wrench: Torque to 8 Nm (71 in-lbs).
• Reconnect each electrical connector until it clicks/locks.

Step 8: Reinstall the engine cover

• Align the cover over the mounting points and push down firmly by hand until it seats.

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✅ After Repair

• Start the engine and let it idle for 30-60 seconds. It should run smooth with no flashing check-engine light.
• Listen for misfires (shaking/uneven idle). If it runs rough, recheck that each coil connector is fully clicked in.
• If you had a check-engine light before, use a scan tool to clear codes and confirm they don’t return.
• Take a short test drive, then recheck for any loose connectors or unusual smells.

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💰 DIY vs Shop Cost

Shop Cost: $250-$450 (parts + labor)

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

You Save: $160-$400 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.0-1.5 hours.

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🎯 Ready to get started?

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