🔧 Altima - Ignition Coil Replacement

You’ll be replacing the ignition coils on your Altima to fix problems like misfires, rough idle, or a check-engine light with coil-related codes. On your 2.5L engine, all four coils sit right on top of the engine and are fairly accessible.

Difficulty Level: Beginner | Estimated Time: 0.5–1.0 hours

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⚠️ Safety & Precautions

• ⚠️ Let the engine cool completely; the engine and plastic parts can get very hot.
• ⚠️ Turn ignition OFF and remove the key from the vehicle before unplugging coils.
• ⚠️ Disconnect the negative battery terminal to avoid accidental short circuits.
• ⚠️ Do not pull on the coil wires; always use the connector release tab.
• ⚠️ Keep all metal tools clear of the battery positive terminal to avoid sparks.

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🔧 Required Tools

You'll need the following tools for this repair:

• 🛠️ 10mm socket
• 🛠️ 3/8" drive ratchet
• 🛠️ 3/8" drive extension (3–6")
• 🛠️ Torque wrench (inch-lb or low-range ft-lb)
• 🛠️ Flathead screwdriver (small)
• 🛠️ Needle-nose pliers
• 🛠️ Plastic trim tool
• 🛠️ Shop rag
• 🛠️ Mechanic gloves
• 🛠️ Safety glasses
• 🛠️ OBD2 scan tool (specialty)

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• 🔩 Ignition coil (2.5L) - Qty: 4 (replace all four together)
• 🔩 Dielectric grease (spark plug/coil grease) - Qty: 1 tube
• 🔩 Battery terminal protector spray - Qty: 1 (optional)
• 🔩 Engine cover clips - Qty: 2–4 (optional, if any break)

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📋 Before You Begin

• Park the Altima on level ground, shift to Park, and set the parking brake.
• Turn off the engine and remove the key from the vehicle.
• Open the hood and secure it with the hood prop rod.
• Disconnect the battery:
  • Loosen the negative (black, “-”) terminal nut with a 10mm socket.
  • Lift the cable off and tuck it 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

• The engine cover is the plastic piece on top of the engine with the Nissan logo.
• If it’s held by clips, gently pry up at the corners with a plastic trim tool.
• If it has bolts, remove them with a 10mm socket and ratchet and lift the cover off.
• Set the cover aside in a clean area.

Step 2: Locate the ignition coils

• You’ll see four identical black ignition coils on top of the engine, each sitting over a spark plug hole.
• Each coil has a small electrical connector and a single 10mm retaining bolt.
• Work on one coil at a time to avoid mix-ups.

Step 3: Disconnect the electrical connector from the first coil

• Press down on the small plastic tab on the coil connector with your thumb or a small flathead screwdriver.
• While holding the tab down, pull the connector straight back by hand.
• If it’s stuck, gently wiggle it, or use needle-nose pliers on the plastic body, not the wires.

Step 4: Remove the ignition coil retaining bolt

• Place a 10mm socket on a 3/8" ratchet with extension.
• Loosen and remove the single 10mm bolt holding the coil to the valve cover.
• Set the bolt aside somewhere safe so it doesn’t fall into the engine bay.

Step 5: Remove the ignition coil

• Grip the top of the coil and gently twist it left and right to break any seal.
• Pull the coil straight up and out of the spark plug tube.
• Inspect the coil boot (the long rubber part) for oil or heavy carbon buildup.
• If you see oil on the boot, the valve cover gasket may be leaking and should be checked later.

Step 6: Prepare the new ignition coil

• Apply a very small amount of dielectric grease inside the rubber boot at the spark plug end.
• Use just a thin smear, not a big glob.
• This helps sealing and future removal but is not strictly required.

Step 7: Install the new ignition coil

• Carefully insert the new coil into the spark plug tube.
• Press straight down until you feel it seat onto the spark plug.
• Line up the bolt hole in the coil bracket with the threaded hole in the valve cover.

Step 8: Reinstall and tighten the coil bolt

• Thread the 10mm bolt in by hand first to avoid cross-threading.
• Use the 10mm socket, extension, and ratchet to snug the bolt.
• Then use a torque wrench with 10mm socket to tighten to:
  • Torque to 8–9 Nm (71–80 in-lbs)
• Do not overtighten; the bolt is small.

Step 9: Reconnect the electrical connector

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

Step 10: Repeat for the remaining three coils

• Move to the next coil and repeat Steps 3 through 9 for each one.
• Work methodically and keep track of all four 10mm bolts.
• Replacing all four now helps long-term reliability.

Step 11: Reinstall the engine cover

• Position the engine cover back over the engine.
• If it uses clips, line them up and press straight down by hand until seated.
• If it uses bolts, install them by hand, then tighten with a 10mm socket and ratchet until snug.

Step 12: Reconnect the battery

• Place the negative (black) cable back on the battery negative post.
• Use a 10mm socket and ratchet to tighten the clamp nut until snug.
• Do not overtighten; just tight enough that the terminal cannot move.

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✅ After Repair

• Start the engine and let it idle. It should run smoothly without misfires or shaking.
• If you have an OBD2 scan tool, connect it and clear any stored ignition or misfire codes.
• Take a short test drive, including light acceleration and a brief highway-speed run if safe.
• After the drive, open the hood and visually confirm all connectors are still fully seated.
• If the check-engine light comes back, re-scan for codes to confirm they are not related to wiring or another issue.

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💰 DIY vs Shop Cost

Shop Cost: $350–$600 (parts + labor)

DIY Cost: $160–$300 (parts only, full set of 4 coils)

You Save: $190–$300 by doing it yourself!

Shop labor rates vary but typically run $100–$150/hour. This repair takes a shop approximately 0.5–1.0 hours.

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🎯 Ready to get started?

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