🔧 Spark Plugs - Replacement

Your Silverado uses coil-on-plug ignition, so each plug sits under its own coil. Replacing them one at a time keeps things organized and helps avoid mix-ups. On the 4.8L V8, access is tight on the rear plugs, but the job is straightforward with the right socket and extensions.

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

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⚠️ Safety & Precautions

• Work on a cold engine only. Hot aluminum threads can be damaged easily.
• Disconnect the negative battery cable before removing coils.
• Keep dirt out of the spark plug wells. Debris can fall into the cylinder.
• Do not use anti-seize on the plug threads unless the plug maker specifically says to. Most modern plugs are pre-coated.
• Do not over-tighten the plugs. This engine uses aluminum cylinder heads.
• Battery disconnect is required.

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🔧 Required Tools

You'll need the following tools for this repair:

• 5/16-inch nut driver
• 10mm socket
• 3/8-inch ratchet
• 3-inch extension
• 6-inch extension
• Spark plug socket, 5/8-inch
• Torque wrench
• Flat-blade trim tool
• Gap gauge
• Dielectric grease
• Flashlight
• Gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs - 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 completely.
• Disconnect the negative battery cable using a 10mm socket.
• Work on one cylinder at a time so plug wire routing stays correct.
• Labeling helps avoid mistakes.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Disconnect power

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

Step 2: Remove the ignition coil cover and air intake parts

• Use a 5/16-inch nut driver and flat-blade trim tool to remove the engine cover or intake ducting that blocks access.
• Set all fasteners aside in order.

Step 3: Remove one ignition coil at a time

• Use a 10mm socket to remove the coil hold-down bolt.
• Twist the coil gently, then pull it straight up.
• Inspect the coil boot for oil, cracks, or burn marks.

Step 4: Remove the old spark plug

• Use a 5/8-inch spark plug socket, ratchet, and extension to remove the plug.
• Turn it slowly at first. If it feels tight, work it back and forth carefully.
• Stop if resistance gets sudden.

Step 5: Prep and install the new spark plug

• Check the new plug gap with a gap gauge if needed.
• Thread the plug in by hand first using the spark plug socket and extension.
• Once seated, use a torque wrench to tighten to 18 Nm (13 ft-lbs).

Step 6: Reinstall the coil

• Apply a small amount of dielectric grease inside the coil boot.
• Push the coil straight onto the plug until fully seated.
• Install the coil bolt with a 10mm socket and tighten to 10 Nm (89 in-lbs).

Step 7: Repeat for all eight cylinders

• Repeat Steps 3 through 6 until all plugs are replaced.
• Keep the coil and plug from each cylinder together so parts stay matched.

Step 8: Reassemble

• Reinstall the intake ducting or engine cover with the 5/16-inch nut driver and flat-blade trim tool.
• Reconnect the negative battery cable with a 10mm socket.

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✅ After Repair

• Start the engine and listen for smooth idle.
• Check for misfire, flashing check engine light, or rough running.
• If the engine runs rough, recheck coil seating and plug wire routing.
• Take a short road test and confirm normal 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 1.5-2.5 hours.

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🎯 Ready to get started?

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