🔧 Malibu - Spark Plug Replacement

On your Malibu, spark plugs wear over time and can cause misfires, rough idle, poor acceleration, and worse fuel economy. Replacing them is a straightforward job: remove the ignition coils, swap the plugs, and torque everything correctly.

Difficulty Level: Intermediate | Estimated Time: 1.0-1.5 hours

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⚠️ Safety & Precautions

• 🔥 Work on a fully cool engine to avoid burns and to prevent damaging aluminum threads in the cylinder head.
• ⚡ Disconnect the negative battery cable if you’re worried about accidentally shorting anything while unplugging coils.
• 🧼 Do not let dirt fall into the spark plug holes; debris can damage the engine.
• 🛑 Do not over-tighten spark plugs; the cylinder head is aluminum.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 1/4" drive ratchet
• 3/8" drive ratchet
• 3/8" drive 6" extension
• 3/8" drive 12" extension
• 5/8" spark plug socket
• Torque wrench (3/8" drive, inch-pound capable)
• Torque wrench (3/8" drive, ft-lb capable)
• Trim removal tool
• Compressed air blow gun
• Feeler gauge (spark plug gap gauge)
• Dielectric grease applicator
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs (iridium, correct OE type) - 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).
• Optional: disconnect the negative battery cable using a 10mm socket.
• Check the under-hood emissions label or owner information for the exact spark plug gap spec; new iridium plugs are usually pre-gapped, but you should verify with a feeler gauge.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover

• Grip the cover and pull straight upward to release the rubber grommets. If a corner is stubborn, use a trim removal tool to lift gently.

Step 2: Unplug the ignition coils

• Locate the 4 ignition coils on top of the engine.
• Release each electrical connector lock and unplug it by hand. Don’t pull on the wires.

Step 3: Remove the ignition coils

• Remove each coil retaining bolt using a 10mm socket and 1/4" drive ratchet.
• Twist the coil slightly to break the seal, then pull it straight up and out.
• Set coils aside in order (so they go back to the same cylinder if you’re reusing them).
• During reassembly: Torque to 10 Nm (89 in-lbs)
• “Ignition coil” = the part that sits on the plug.

Step 4: Clean around the spark plug wells

• Blow out each spark plug hole with compressed air blow gun before removing the plug.
• This prevents grit from falling into the cylinder.

Step 5: Remove the old spark plugs

• Install a 5/8" spark plug socket on a 3/8" drive ratchet with a 6" extension (use the 12" extension if needed for reach).
• Turn counterclockwise to loosen, then remove the plug slowly.
• If a plug feels stuck, stop and tighten slightly, then loosen again (prevents thread damage).

Step 6: Check the new plug gap and prepare the coils

• Verify each new plug’s gap using a feeler gauge and match the spec from your Malibu’s under-hood emissions label/info.
• Apply a small dab of dielectric grease inside each coil boot using a dielectric grease applicator. Just a thin film.
• “Dielectric grease” helps prevent moisture and eases removal later.

Step 7: Install the new spark plugs

• Thread each plug in by hand first using the 5/8" spark plug socket and extension only (no ratchet) to avoid cross-threading.
• Once seated, tighten with a torque wrench (3/8" drive, ft-lb capable): Torque to 18 Nm (13 ft-lbs)
• If it won’t thread easily, back out and restart.

Step 8: Reinstall ignition coils and engine cover

• Push each coil straight down onto its plug until fully seated.
• Install coil bolts using a 10mm socket, then use a torque wrench (3/8" drive, inch-pound capable): Torque to 10 Nm (89 in-lbs)
• Reconnect all coil electrical connectors by hand until they click.
• Reinstall the engine cover by aligning it and pressing down firmly.
• If you disconnected the battery, reconnect the negative cable using a 10mm socket and tighten snugly.

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✅ After Repair

• Start the engine and let it idle for 1-2 minutes. It should run smooth with no shaking.
• Check that the Check Engine Light stays off.
• Take a short test drive and recheck for any odd hesitation or flashing warning lights.
• If you had a misfire code before, clear codes with a scan tool and confirm they don’t return.

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💰 DIY vs Shop Cost

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

DIY Cost: $40-$120 (parts only)

You Save: $130-$410 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?

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.