🔧 Spark Plugs - Replacement

Your spark plugs wear out over time and can cause misfires, rough idle, poor fuel economy, or hard starting. On your Silverado, the job is straightforward, but the rear plugs take patience because access is tighter near the firewall.

Difficulty Level: Intermediate | Estimated Time: 2-4 hours

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⚠️ Safety & Precautions

• Let the engine cool completely before starting. Hot exhaust parts can burn you.
• Disconnect the negative battery cable before removing ignition coils. This reduces the chance of a short or accidental start.
• Work carefully around the ignition coils. They carry high voltage when the engine runs.
• Keep dirt out of the spark plug wells. Debris can fall into the cylinder and cause damage.
• Do not use anti-seize on the spark plug threads unless the plug maker specifically calls for it.
• Use hand tools first when loosening plugs. If a plug feels stuck, stop and work it out slowly.

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🔧 Required Tools

You'll need the following tools for this repair:

• 1/4-inch drive ratchet
• 3/8-inch drive ratchet
• 10mm socket
• 5/8-inch spark plug socket
• 6-inch extension
• 12-inch extension
• Universal joint socket adapter
• Torque wrench
• Trim clip tool
• Flat-blade screwdriver
• Needle-nose pliers
• Compressed air nozzle
• Safety glasses
• Nitrile gloves

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plug set - Qty: 8
• Ignition coil boots - Qty: 8
• Dielectric grease - Qty: 1

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📋 Before You Begin

• Park on level ground and set the parking brake.
• Let the engine cool fully.
• Disconnect the negative battery terminal before removing coils.
• Work on one cylinder at a time so the coil and plug wires stay organized.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover

• Use your hands to lift the plastic engine cover off the top of the engine.
• If it feels stuck, gently wiggle it upward instead of forcing it.

Step 2: Disconnect the battery

• Use a 10mm socket to loosen and remove the negative battery cable.
• Move the cable aside so it cannot touch the battery terminal.

Step 3: Remove the ignition coils

• Use a 10mm socket and ratchet to remove the coil hold-down bolts.
• Unplug each ignition coil connector by pressing the lock tab and pulling the connector straight off.
• Pull each coil straight up out of the spark plug well.
• Keep each coil in cylinder order.

Step 4: Clean the spark plug wells

• Use compressed air nozzle to blow dirt out of each plug well before removing the plugs.
• This helps keep debris out of the cylinder.

Step 5: Remove the old spark plugs

• Use a 5/8-inch spark plug socket, extension, and ratchet to loosen each plug.
• Turn slowly and keep the socket straight so the plug does not bind.
• Remove one plug at a time.

Step 6: Inspect and prep the new plugs

• Check the new spark plugs for shipping damage.
• Install them dry unless the plug manufacturer says otherwise.
• Do not adjust iridium plug tips.

Step 7: Install the new spark plugs

• Thread each plug in by hand first using the spark plug socket and extension.
• This helps prevent cross-threading the cylinder head.
• Once seated, use the torque wrench to tighten each plug to 18 N·m (13 ft-lbs).

Step 8: Reinstall the ignition coils

• Apply a small amount of dielectric grease inside each coil boot.
• Push each coil straight down onto its spark plug.
• Reinstall the coil bolts with a 10mm socket and tighten snugly.
• Reconnect each coil connector until it clicks.

Step 9: Reconnect the battery and reinstall the cover

• Reconnect the negative battery cable with a 10mm socket.
• Reinstall the engine cover by pressing it straight down into place.

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✅ After Repair

• Start the engine and let it idle.
• Listen for rough running, ticking, or a misfire.
• Check that no warning lights are on.
• Take a short test drive and confirm smooth acceleration.
• If the check engine light returns, scan for misfire codes.

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💰 DIY vs Shop Cost

Shop Cost: $280-$550 (parts + labor)

DIY Cost: $80-$180 (parts only)

You Save: $200-$370 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 2-4 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.