🔧 CX-5 - Spark Plug Replacement

On your CX-5, the spark plugs fire the air/fuel mix in each cylinder. Replacing worn plugs helps prevent misfires, rough idle, poor fuel economy, and hard starts.

Difficulty Level: Intermediate | Estimated Time: 1.0-2.0 hours

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⚠️ Safety & Precautions

• ⚠️ Work on a fully cool engine to avoid burns and to protect the aluminum threads in the cylinder head.
• ⚠️ Keep dirt out of the spark plug tubes; debris can fall into the cylinder.
• ⚠️ If you disconnect the battery, you may lose saved settings; wait 2–3 minutes after key-off before unplugging engine connectors.

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🔧 Required Tools

You'll need the following tools for this repair:

• 8mm socket
• 10mm socket
• 3/8" drive ratchet
• 3/8" drive extension set (3" and 6")
• 14mm spark plug socket (thin-wall)
• Torque wrench (3/8" drive, 10-30 ft-lbs range)
• Flat trim tool
• Compressed air blow gun
• Shop vacuum
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs (OEM-spec iridium) - 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 (ideally 1+ hour).
• Have a clear table to keep coil packs in order (cylinder 1–4).

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover

• Grip the engine cover and pull upward firmly to release the rubber grommets (no bolts).
• If it feels stuck, use a flat trim tool to gently pry up at a corner.

Step 2: Unplug and remove the ignition coils

• At each coil, press the connector tab and unplug it by hand. Don’t pull on the wires.
• Use an 8mm socket with a 3/8" drive ratchet to remove the coil hold-down bolt.
• Twist the coil slightly, then pull straight up to remove it.
• Uncommon term: The “ignition coil” sits on top of the spark plug and makes the high voltage for the spark.

Step 3: Clean the spark plug tubes before removal

• Use compressed air blow gun to blow dirt out of each spark plug well.
• If there’s loose dirt sitting on top, use a shop vacuum first, then blow air.

Step 4: Remove the old spark plugs

• Install the 14mm spark plug socket (thin-wall) on a 3/8" drive extension and 3/8" drive ratchet.
• Loosen each plug counterclockwise and lift it out carefully with the socket.
• Uncommon tool: A “thin-wall” spark plug socket is slimmer so it fits tight plug tubes without getting stuck.

Step 5: Install the new spark plugs (start by hand)

• Put the new plug into the 14mm spark plug socket (thin-wall) and extension.
• Thread it into the hole by hand using only the extension (no ratchet at first) to avoid cross-threading.
• Once fully seated by hand, use the torque wrench to tighten: Torque to 15-20 Nm (11-15 ft-lbs).
• Tip: If it doesn’t turn easily, back out and retry.

Step 6: Reinstall coils and connectors

• Apply a tiny amount of dielectric grease inside each coil boot. Only a thin smear.
• Push each coil straight down until it seats on the plug.
• Install the coil bolt using an 8mm socket and 3/8" drive ratchet, then snug evenly.
• Reconnect each electrical connector until it clicks.
• Uncommon term: “Dielectric grease” is a non-conductive grease that helps prevent moisture and sticking in the rubber boot.

Step 7: Reinstall the engine cover

• Align the cover with the mounting pegs and press down firmly to seat the grommets.

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✅ After Repair

• Start the engine and let it idle for 30–60 seconds; it should run smooth.
• If you get a check engine light or a rough idle, re-check that every coil connector is fully clicked in.
• Take a short test drive and confirm no hesitation under light acceleration.

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💰 DIY vs Shop Cost

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

DIY Cost: $50-$120 (parts only)

You Save: $200-$330 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.