🔧 Focus - Spark Plug Replacement

Replacing the spark plugs on your Focus helps restore smooth starting, proper fuel economy, and clean engine performance. The 2.0L engine uses four spark plugs, one for each cylinder, located under the ignition coils on top of the engine.

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

---

⚠️ Safety & Precautions

• ⚠️ Let the engine cool completely before starting. Spark plugs thread into the aluminum cylinder head, and hot aluminum can be damaged easily.
• ⚠️ Disconnect the negative battery cable to prevent accidental ignition system activity.
• ⚠️ Keep dirt out of the spark plug wells. Debris can fall into the engine when a plug is removed.
• ⚠️ Do not overtighten spark plugs. The cylinder head is aluminum and the threads can strip.

---

🔧 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 3/8-inch drive
• Compressed air blow gun
• Spark plug gap gauge
• Needle-nose pliers
• Dielectric grease
• Clean shop towels
• Safety glasses
• Nitrile gloves

---

🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs - Qty: 4
• Ignition coil boots - Qty: 4, optional if cracked, oil-soaked, or torn

---

📋 Before You Begin

• 🅿️ Park your Focus on level ground and set the parking brake.
• 🧊 Make sure the engine is cold to the touch before removing spark plugs.
• 🔋 Use a 10mm socket to loosen and disconnect the negative battery cable. Move it aside so it cannot touch the battery post.
• 📏 Check the new spark plug gaps with a spark plug gap gauge. A gap gauge measures the tiny space between the center electrode and ground strap.
• ⚠️ Use the correct pre-gapped plugs for your Focus. Do not forcefully bend fine-wire iridium or platinum electrodes.

---

🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the Engine Cover if Equipped

• Use your hands to gently lift the plastic engine cover straight upward if your Focus has one.
• If fasteners are fitted, use an 8mm socket to remove them.
• Set the cover aside in a safe place.
• Tip: Pull evenly, not sideways.

Step 2: Locate the Ignition Coils

• The ignition coils are the four black electrical units on top of the engine.
• An ignition coil creates the high voltage needed to fire each spark plug.
• Each coil sits directly over one spark plug.

Step 3: Clean Around the Ignition Coils

• Put on safety glasses.
• Use a compressed air blow gun to blow dirt away from the coil area.
• Wipe loose dust with clean shop towels.
• Do not spray liquid cleaner into the spark plug wells.

Step 4: Disconnect the Ignition Coil Connectors

• Press the locking tab on each ignition coil electrical connector with your finger.
• If the tab is stiff, use needle-nose pliers gently on the connector lock only.
• Pull the connector straight back from the coil.
• Do not pull on the wires.
• Tip: Work one plug at a time.

Step 5: Remove the Ignition Coils

• Use an 8mm socket and 3/8-inch ratchet to remove the ignition coil retaining bolt from one coil.
• Twist the ignition coil gently by hand to loosen the rubber boot.
• Pull the coil straight upward and out of the spark plug well.
• Inspect the rubber boot. Replace the boot if it is cracked, swollen, torn, or oil-soaked.

Step 6: Clean the Spark Plug Well

• Use the compressed air blow gun to blow debris out of the spark plug well.
• A spark plug well is the deep tube where the spark plug sits.
• Keep your face away from the well while blowing air.
• Use a clean shop towel to catch loose dust around the opening.

Step 7: Remove the Old Spark Plug

• Place the 5/8-inch spark plug socket onto the 6-inch extension and 3/8-inch ratchet.
• A spark plug socket has a rubber insert or magnet that holds the plug while lifting it out.
• Lower the socket straight down onto the spark plug.
• Turn counterclockwise slowly to loosen the spark plug.
• Once loose, spin it out by hand using the extension.
• Lift the old spark plug straight out.

Step 8: Check the New Spark Plug

• Use a spark plug gap gauge to verify the new plug gap.
• For your Focus 2.0L, use plugs matched to the factory specification supplied by the parts catalog.
• Do not apply anti-seize unless the spark plug manufacturer specifically requires it.
• Most modern plated spark plugs are installed dry.

Step 9: Install the New Spark Plug by Hand

• Insert the new spark plug into the 5/8-inch spark plug socket.
• Lower it carefully into the spark plug well using the 6-inch extension.
• Turn the extension clockwise by hand only for several turns.
• If it does not turn easily, stop and restart. This prevents cross-threading, which means the plug is going in crooked.
• Use the torque wrench with the 5/8-inch spark plug socket to tighten the plug.
• Torque to 15 Nm (11 ft-lbs)
• Tip: Hand-start every spark plug.

Step 10: Reinstall the Ignition Coil

• Apply a small amount of dielectric grease inside the end of the ignition coil boot.
• Dielectric grease helps seal out moisture but does not conduct electricity.
• Push the ignition coil straight down onto the spark plug until fully seated.
• Use the 8mm socket and torque wrench to reinstall the coil retaining bolt.
• Torque to 6 Nm (53 in-lbs)

Step 11: Reconnect the Ignition Coil Connector

• Push the electrical connector onto the ignition coil by hand.
• Listen or feel for the locking tab to click into place.
• Gently tug the connector to confirm it is locked.

Step 12: Repeat for the Remaining Spark Plugs

• Repeat Steps 4 through 11 for the other three spark plugs.
• Use the 8mm socket for each coil bolt.
• Use the compressed air blow gun before removing each spark plug.
• Use the 5/8-inch spark plug socket for each spark plug.
• Use the torque wrench on every new spark plug.

Step 13: Reinstall the Engine Cover and Battery Cable

• Reinstall the engine cover by pressing it straight down by hand, or use the 8mm socket if fasteners are equipped.
• Reconnect the negative battery cable.
• Use the 10mm socket to tighten the negative battery terminal snugly.
• Do not overtighten the battery terminal clamp.

---

✅ After Repair

• ✅ Start your Focus and let it idle for 1-2 minutes.
• ✅ The engine should idle smoothly with no shaking or flashing check engine light.
• ✅ If the engine misfires, shut it off and recheck that every ignition coil connector is fully seated.
• ✅ Take a short test drive and listen for smooth acceleration.
• ✅ If the battery was disconnected, reset the clock and one-touch window function if needed.

---

💰 DIY vs Shop Cost

Shop Cost: $180-$320 (parts + labor)

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

You Save: $145-$230 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.7-1.2 hours.

---

🎯 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.