🔧 CX-5 - Spark Plug Replacement

On your CX-5, the spark plugs sit under the ignition coils on top of the engine. Replacing them restores smooth starts, fuel economy, and helps prevent misfires as mileage builds.

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

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⚠️ Safety & Precautions

• ⚠️ Work on a fully cool engine to avoid stripped threads and burns.
• ⚠️ Do not overtighten plugs—aluminum cylinder head threads can strip.
• ⚠️ Keep dirt out of the plug wells; blow/vacuum before removing plugs.
• ⚠️ Battery disconnect is not required, but keep the ignition OFF and the key/fob away from the vehicle while you unplug coils.

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🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Nitrile gloves
• 10mm socket
• 3/8" drive ratchet
• 3/8" drive extension set (3" and 6")
• 14mm spark plug socket (thin-wall, rubber insert)
• Torque wrench (3/8" drive, 5–30 ft-lb range)
• Trim clip tool
• Compressed air blow gun
• Shop vacuum
• Wire-style spark plug gap gauge
• Small pick tool

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Iridium spark plugs (OEM-style for 2.5L) - 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).
• Open the hood and remove any loose items around the engine bay.
• If you have compressed air, set it up now; you’ll use it to clean the plug wells before removal.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover

• Grip the plastic engine cover and pull upward firmly to release it from the rubber grommets.
• If a corner feels stuck, use a trim clip tool to gently pry upward.

Step 2: Unplug the ignition coils

• There are 4 coils on top of the engine (one per cylinder).
• Press the electrical connector tab and pull the connector off each coil.
• If the tab is stubborn, use a small pick tool to gently lift the lock while pulling. Don’t pull on the wires.

Step 3: Remove the ignition coils

• Use a 10mm socket with a 3/8" drive ratchet to remove the 10mm bolt holding each coil.
• Twist the coil slightly, then pull it straight up and out of the spark plug tube.
• Set coils aside in order so they go back to the same cylinder.
• During reassembly: Torque to 8–10 Nm (71–89 in-lbs)

Step 4: Clean the spark plug wells

• Use a shop vacuum to remove loose dirt around the tubes.
• Then use compressed air blow gun to blow out each plug well.
• This prevents grit from falling into the cylinder when the plug comes out.

Step 5: Remove the old spark plugs

• Install a 14mm spark plug socket (thin-wall, rubber insert) on a 3/8" drive extension (6") and 3/8" drive ratchet.
• Lower the socket straight down onto the plug and loosen counterclockwise.
• Once loose, continue turning by hand with the extension to avoid cross-threading on the way out.
• Lift the plug out with the socket (the rubber insert helps hold it).

Step 6: Check and prepare the new spark plugs

• Verify the new plugs match the old plugs in length and seat style.
• Use a wire-style spark plug gap gauge to confirm the gap is within spec.
• On iridium plugs, do not “re-gap” by prying on the center electrode (it can crack). If the gap is off, exchange the plug.
• Apply a tiny dab of dielectric grease inside each coil boot (this helps prevent moisture and makes future removal easier).

Step 7: Install the new spark plugs

• Place a new plug into the 14mm spark plug socket and lower it straight into the tube.
• Thread the plug in by hand using only the extension (no ratchet) until it seats. This prevents cross-threading.
• Switch to a torque wrench (3/8" drive, 5–30 ft-lb range) and tighten each plug: Torque to 15–20 Nm (11–15 ft-lbs)
• Do not use anti-seize unless the plug maker specifically requires it (most OEM-style plated plugs do not).

Step 8: Reinstall ignition coils and connectors

• Push each coil straight down until fully seated on the plug.
• Install the coil hold-down bolt using a 10mm socket and tighten: Torque to 8–10 Nm (71–89 in-lbs)
• Reconnect each coil electrical connector until it clicks.

Step 9: Reinstall the engine cover

• Align the cover with the mounting points and press down firmly until it snaps into place.

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✅ After Repair

• Start the engine and let it idle for 30–60 seconds; it should run smooth.
• Listen for any “ticking” (could indicate a loose plug) and recheck torque if needed.
• If you had a check-engine light for a misfire, you may need a scan tool to clear codes after the fix.
• Take a short test drive and confirm there’s 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: $130-$400 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?

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