F-150 - Spark Plug Replacement 🔧

Got it—2015 F-150 Platinum, 5.0L V8. I’ll walk you through this like a first-time DIYer.

Quick check first: Are you working with basic hand tools only (ratchets, sockets, pliers, screwdrivers), or do you also have a torque wrench? This changes how I explain tightening.

Also, will you be replacing the ignition coils too, or just the spark plugs?

Parts You Need 📦

• ✅ 8 spark plugs (one per cylinder)
  • Ford OEM spec: typically Motorcraft SP-534 (CYFS-12Y-3) or supersession for the 5.0L
  • Use pre-gapped plugs for this engine; do not change the gap unless the box says to check/adjust.
• ✅ Optional: 8 new ignition coil boots (rubber sleeves on the coils)
• ✅ Small packet of dielectric grease (non-conductive grease for electrical boots)
• ✅ Small packet of anti-seize (only if plug manufacturer allows it; many say “no anti-seize”)

Tools You Need 🧰

• 🛠️ 3/8" drive ratchet (standard hand wrench with a round head and handle)
• 🛠️ Spark plug socket, 5/8" with rubber insert or magnet
  • This is a special deep socket that grips the plug so it doesn’t fall.
• 🛠️ Socket extensions
  • One short (3") and one medium/long (6") will help reach all plugs.
• 🛠️ 10 mm socket (for ignition coil bolts)
• 🛠️ Torque wrench (3/8" drive)
  • Tool that lets you tighten to a specific torque value; very helpful for spark plugs.
• 🛠️ Small flat screwdriver or pick tool
  • For gently lifting electrical connector locks.
• 🛠️ Compressed air (canned air or small compressor)
  • To blow dirt out of the spark plug wells before removal.
• 🛠️ Fender cover or old towel
  • Protects paint and gives you a place to lean.
• 🛠️ Optional: Swivel (universal) joint for your socket
  • Helps reach the rear plugs near the firewall.

Important Specs 📏

• 📌 Spark plug torque (5.0L Coyote V8): 11–15 lb-ft (15–20 N·m)
  • Ford service spec is about 13 lb-ft (18 N·m) for tapered-seat plugs.
• 📌 Ignition coil bolt torque: about 62 in-lb (7 N·m) (snug, not gorilla tight)

Safety First ⚠️

• ⚠️ Engine cool only. Let the engine cool completely. Hot aluminum heads strip easily.
• ⚠️ Disconnect the negative battery cable.
  • Use a 10 mm wrench, remove the negative (black) terminal, and tuck it aside.
• ⚠️ No dirt in cylinders. Always blow out around each plug before removing it.

F-150 - Accessing the Spark Plugs 🔍

The 5.0L has a coil-on-plug system: one ignition coil on top of each spark plug.

Step 1 – Remove Engine Cover (if equipped)

• 🧩 If your F-150 has a plastic engine cover:
  • Remove any visible 10 mm bolts or plastic push-pins.
  • Lift the cover straight up; it may be held by rubber grommets.

Step 2 – Identify Coils

• 🔎 On each side of the engine (left and right banks), you’ll see:
  • Black rectangular ignition coils with a 2-wire connector.
  • Each coil sits directly over a spark plug.

F-150 - Replacing One Spark Plug (Repeat 8 Times) 🔁

Step 3 – Unplug the Ignition Coil

• 🔌 Press the tab on the coil’s electrical connector.
  • If it’s stuck, gently lift the tab with a small flat screwdriver while pulling the connector off.

Step 4 – Remove the Ignition Coil

• 🔧 Use a 10 mm socket and ratchet to remove the single bolt holding the coil.
• 🤏 Twist the coil gently and pull it straight up.
  • You’ll see a long rubber boot; that’s normal.
• 👀 Inspect the boot:
  • Look for oil, cracks, or burn marks. If damaged, replace the boot or coil.

Step 5 – Clean Around the Spark Plug

• 💨 Use compressed air to blow out the spark plug well.
  • Do this before loosening the plug.

Step 6 – Remove the Old Spark Plug

• 🔧 Install the 5/8" spark plug socket on an extension and ratchet.
• ⬇️ Lower it straight down into the well until it seats on the plug.
• 🔄 Turn counterclockwise to loosen.
  • If it feels very tight, do not force it. Turn a little loose, then a little tight, back and forth, to break carbon.
• ⬆️ Once loose, spin it out by hand with the extension and pull the plug up with the socket.

Step 7 – Prepare the New Spark Plug

• 👀 Compare old and new:
  • Same thread length, same seat style, same tip length.
• 📏 If the plug maker says to check gap, use a gap gauge (coin-like tool with numbers) and confirm it matches the spec on the plug box. Don’t bend the fine wire unless instructed.
• 🧴 If allowed by the plug manufacturer:
  • Apply a tiny smear of anti-seize on the threads only, avoiding the tip.

Step 8 – Install the New Spark Plug

• 🖐️ Put the new plug into the spark plug socket so it’s held by the rubber/magnet.
• ⬇️ Carefully lower it into the hole, keeping it straight.
• 🤲 Hand-thread first:
  • Turn the extension by hand clockwise several turns.
  • If it doesn’t spin easily, back out and try again. Never force it with the ratchet at first.
• 🔧 Once hand-tight, attach the ratchet and snug it.
• 📌 If using a torque wrench:
  • Set to 13 lb-ft (18 N·m) and tighten until it clicks once.
• 📌 If you do NOT have a torque wrench:
  • Snug the plug until it seats, then turn about 1/8–1/4 turn more. It should be firm, not “crushing tight.”

Step 9 – Reinstall the Ignition Coil

• 🧴 Put a small dab of dielectric grease inside the rubber boot tip.
• ⬇️ Push the coil straight down onto the plug until fully seated.
• 🔧 Reinstall the 10 mm coil bolt:
  • Tighten to about 62 in-lb (7 N·m) or just snug with a small ratchet.
• 🔌 Plug the electrical connector back in until it clicks.

Step 10 – Repeat for All 8 Cylinders

• 🔁 Work one cylinder at a time:
  • This avoids mixing up coils or connectors.
• 🧠 The rear cylinders near the firewall are tighter:
  • Use your longer extension and swivel joint if needed.

F-150 - Reassembly & Final Checks ✅

• 🧩 Reinstall the engine cover and any bolts/push-pins.
• 🔋 Reconnect the negative battery terminal and tighten the 10 mm nut snugly.
• 🚗 Start the engine:
  • It should idle smoothly with no misfire or check engine light.
  • A brief rough idle for 1–2 seconds is okay as the computer adjusts, but it should quickly smooth out.
• 🛣️ Take a short test drive:
  • Check for smooth acceleration and no hesitation.

Tips & Tricks 💡

• 🧠 Do one side of the engine at a time so you don’t get overwhelmed.
• 🧽 Keep a magnet-on-a-stick handy in case you drop a bolt.
• 📸 Take a quick photo of coil and wiring layout before you start, just in case.

HowToo makes it easy: below this answer you’ll see spark plugs, coil boots, dielectric grease, anti-seize, and the correct spark plug socket and torque wrench we sell. You can add them to your cart right from the parts section.

Reply with:

• Whether you have a torque wrench
• Which side you want to start on (driver or passenger)

and I can give you a very short, plug-by-plug game plan for that side.