🔧 Altima - Ignition Coil Replacement

You’ll be removing the plastic engine cover, unplugging each ignition coil, and swapping it with a new one. This restores strong spark and can fix misfires or rough running.

Difficulty Level: Beginner | Estimated Time: 1-1.5 hours

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⚠️ Safety & Precautions

• 🔸Always work with the engine off, in Park, and the parking brake set.
• 🔸Let the engine cool completely; coils sit on a hot engine and can burn you.
• 🔸Disconnect the negative battery cable to avoid short circuits and accidental starts.
• 🔸Do not pull on wires; only pull on connectors and parts.
• 🔸Keep tools and hardware away from the open spark plug holes to prevent dropping anything inside.

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🔧 Required Tools

You'll need the following tools for this repair:

• 🔸10mm socket
• 🔸1/4" drive ratchet
• 🔸1/4" drive extension (3"-6")
• 🔸Small flathead screwdriver
• 🔸Torque wrench (inch-lb or low-range Nm)
• 🔸Needle-nose pliers
• 🔸Shop rag
• 🔸Mechanic gloves
• 🔸Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• 🔸Ignition coil pack set (4 coils) - Qty: 1 set (replace in full set recommended)
• 🔸Ignition coil mounting bolts (10mm, if corroded) - Qty: up to 4
• 🔸Dielectric grease - Qty: 1 tube
• 🔸Battery terminal protector spray - Qty: 1 (optional)

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📋 Before You Begin

• Park the Altima on level ground, shift to Park, and set the parking brake.
• Open the hood and secure it with the prop rod.
• Turn off all electrical accessories (lights, radio, AC).
• Disconnect the negative battery terminal using the 10mm socket and move the cable aside so it cannot spring back.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover

• Use the 10mm socket and ratchet to remove any visible bolts holding the plastic engine cover (some covers just pull up off rubber grommets).
• Lift the engine cover straight up and set it aside.
• Pull evenly to avoid cracking plastic.

Step 2: Locate the ignition coils

• On the 2.5L engine, you will see four ignition coils on top of the engine, one for each cylinder, in a row.
• Each coil is a black unit with an electrical connector and a single 10mm bolt.
• Work on one coil at a time to avoid mix-ups.

Step 3: Disconnect the electrical connector from the first coil

• Use the small flathead screwdriver to gently lift the locking tab on the coil’s electrical connector.
• While lifting the tab, pull the connector straight back with your fingers (or needle-nose pliers if needed, very gently).
• Do not pry the connector off sideways; it can crack.

Step 4: Remove the coil hold-down bolt

• Use the 10mm socket, extension, and ratchet to remove the bolt holding the coil to the valve cover.
• Keep the bolt in a safe place; you’ll reuse it if it’s in good condition.
• Place bolts in a small tray so none are lost.

Step 5: Remove the ignition coil

• Grip the top of the coil and twist it gently left and right to break it free from the spark plug.
• Pull the coil straight up and out of the spark plug well.
• If it feels stuck, continue gentle twisting; do not yank hard.

Step 6: Inspect the spark plug well (quick check)

• With the coil removed, look down into the spark plug well using a light.
• Check for oil or coolant in the well; it should be dry. If you see fluid, there may be another issue (like a valve cover leak).
• Use a shop rag around the opening to wipe any dirt away from the top area (do not drop anything in).

Step 7: Prepare the new ignition coil

• Take a new coil from the set.
• Apply a very thin smear of dielectric grease inside the rubber boot at the tip (this helps prevent moisture and makes future removal easier).
• Do not pack the boot full of grease.

Step 8: Install the new ignition coil

• Insert the new coil straight down into the spark plug well, making sure the boot goes over the spark plug.
• Press down gently until you feel it “seat” on the plug.
• Align the bolt hole on the coil bracket with the threaded hole in the valve cover.

Step 9: Reinstall and torque the coil bolt

• Start the 10mm bolt by hand to avoid cross-threading.
• Use the 10mm socket and ratchet to snug the bolt.
• Then use a torque wrench with the 10mm socket and torque the coil bolt to 8 Nm (71 in-lb).
• Do not overtighten; the threads are in aluminum.

Step 10: Reconnect the electrical connector

• Push the connector straight onto the coil until you hear or feel a click.
• Gently tug on the connector to confirm it is locked in place.

Step 11: Repeat for the remaining coils

• Repeat Steps 3–10 for each of the remaining three coils, one at a time.
• It’s a good idea to replace all four coils at once if you’re fixing a misfire on a higher-mileage engine.
• Consistent age of coils helps long-term reliability.

Step 12: Reinstall the engine cover

• Place the engine cover back on top of the engine, lining up any rubber grommets and bolt holes.
• Press down to seat the cover onto its mounts.
• Use the 10mm socket and ratchet to reinstall and snug any mounting bolts. These are just snug; do not overtighten.

Step 13: Reconnect the battery

• Reattach the negative battery cable to the battery post.
• Use the 10mm socket and ratchet to tighten the terminal nut firmly, but do not crush it.
• Optional: spray a light coat of battery terminal protector on the terminal.

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✅ After Repair

• 🔸Start the engine and let it idle. It should run smoothly without shaking or misfiring.
• 🔸If the check engine light was on for a misfire, it may clear on its own after several drive cycles, or you can clear it with an OBD-II scan tool.
• 🔸Take a short test drive, checking for smooth acceleration and no hesitation.
• 🔸After the drive, recheck under the hood to ensure all connectors are still fully seated and there are no loose parts.

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💰 DIY vs Shop Cost

Shop Cost: $350-$600 (parts + labor) for all four coils

DIY Cost: $120-$250 (parts only, full set of coils)

You Save: $230-$350 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.8-1.0 hours.

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🎯 Ready to get started?

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