🔧 C-HR - Spark Plug Replacement

On your C-HR, the spark plugs sit under the ignition coils on top of the engine. Replacing them restores smooth starting, fuel economy, and prevents misfires as the plugs wear over time.

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 damaged threads.
• ⚠️ Keep dirt out of the spark plug holes; debris can damage the engine.
• ⚠️ Do not over-tighten spark plugs; aluminum cylinder head threads strip easily.
• ⚠️ Battery disconnect is not required, but keep the ignition OFF and the key/fob away from the car while connectors are unplugged.

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🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Nitrile gloves
• 3/8" drive ratchet
• 3/8" drive torque wrench (10–30 Nm range)
• 10mm socket
• 14mm thin-wall spark plug socket (magnetic or rubber insert)
• 6" extension (3/8" drive)
• Compressed air blow gun
• Trim clip tool
• Small flathead screwdriver
• Shop rags
• Dielectric grease

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Iridium spark plugs (OEM-spec) - Qty: 4

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📋 Before You Begin

• Park on level ground and let the engine cool completely.
• Open the hood and remove any loose items around the engine bay.
• Lay out 4 new plugs and keep them in their boxes until installation.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover (if equipped)

• Grab the cover with both hands and pull straight up to pop it off the rubber grommets.
• Set it aside where it won’t get stepped on.

Step 2: Unplug and remove the ignition coils

• An ignition coil (often called a “coil pack”) is the small module sitting on top of each spark plug.
• Use a small flathead screwdriver to gently lift the connector lock tab (if present), then unplug the coil connector.
• Use a 10mm socket and 3/8" ratchet to remove the coil hold-down bolt.
• Twist the coil slightly, then pull straight up to remove it.
• Keep coils in order, one per cylinder.

Step 3: Clean the spark plug wells

• Use a compressed air blow gun to blow out dirt around each plug hole before removing the plug.
• Wipe around the opening with shop rags if needed.

Step 4: Remove the old spark plugs

• A spark plug socket is a special socket that grips the plug so it doesn’t fall out.
• Install the 14mm thin-wall spark plug socket with a 6" extension on the 3/8" ratchet.
• Turn counterclockwise to loosen, then remove the plug carefully.
• Repeat for all four cylinders.

Step 5: Install the new spark plugs

• Verify each new plug matches the old plug’s length and seat shape.
• Do not adjust the gap on iridium plugs.
• Thread each new plug in by hand first using the spark plug socket and extension (no ratchet at first) to avoid cross-threading.
• Once seated, use a 3/8" drive torque wrench to tighten each plug: Torque to 18 Nm (13 ft-lbs).
• Avoid anti-seize on plated plugs.

Step 6: Reinstall the ignition coils

• Apply a tiny amount of dielectric grease inside each coil boot.
• Push the coil straight down until you feel it fully seat on the plug.
• Reinstall the coil bolt using a 10mm socket, then tighten with a torque wrench: Torque to 10 Nm (89 in-lbs).
• Reconnect the electrical connector until it clicks/locks.

Step 7: Reinstall the engine cover

• Align the cover with the mounting points and press down firmly to snap it into place.

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✅ After Repair

• Start the engine and let it idle for 30–60 seconds; it should run smooth with no shaking.
• Take a short test drive and confirm there’s no check-engine light.
• If you get a misfire or rough idle, re-check each coil connector is fully clicked in.

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💰 DIY vs Shop Cost

Shop Cost: $220-$420 (parts + labor)

DIY Cost: $45-$110 (parts only)

You Save: $175-$310 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.