🔧 Traverse - Spark Plug Replacement

Replacing the spark plugs on your Traverse helps restore smooth idle, easy starting, fuel economy, and proper ignition performance. The 3.6L V6 uses six spark plugs and individual ignition coils, with the rear bank being tighter to access than the front bank.

Difficulty Level: Intermediate | Estimated Time: 2.5-4 hours

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⚠️ Safety & Precautions

• ⚠️ Work only on a completely cool engine to avoid burns and damaged aluminum threads.
• ⚠️ Disconnect the negative battery cable before unplugging ignition coils.
• ⚠️ Do not drop dirt into the spark plug wells. A spark plug well is the deep tube where the spark plug sits.
• ⚠️ Start each new spark plug by hand before tightening. Cross-threading can damage the cylinder head.
• ⚠️ Do not use anti-seize on modern coated spark plug threads unless the plug maker specifically requires it.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 8mm socket
• 3/8-inch drive ratchet
• 1/4-inch drive ratchet
• 5/8-inch spark plug socket
• 3-inch extension
• 6-inch extension
• 10-inch extension
• 3/8-inch universal joint adapter
• Torque wrench, inch-pound range
• Torque wrench, foot-pound range
• Plastic trim removal tool
• Needle-nose pliers
• Compressed air blow gun
• Spark plug gap gauge
• Dielectric grease
• Shop towels
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Iridium spark plugs - Qty: 6
• Upper intake manifold gasket set - Qty: 1
• Throttle body gasket - Qty: 1

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📋 Before You Begin

• 🅿️ Park your Traverse on level ground, shift to Park, and set the parking brake.
• ❄️ Let the engine cool fully before starting.
• 🔋 Use a 10mm socket to disconnect the negative battery cable, then move the cable aside so it cannot spring back.
• 🧼 Clean loose dirt from the top of the engine before removing parts.
• 📏 Verify the new spark plugs are pre-gapped correctly. For the 3.6L V6, use 0.043 in unless the plug box says “do not gap.”

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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 straight upward from its rubber mounting grommets.
• Set the cover aside in a safe place.
• Pull evenly, not sideways.

Step 2: Disconnect the Air Intake Tube

• Use an 8mm socket to loosen the hose clamp at the throttle body.
• Use an 8mm socket to loosen the hose clamp at the air filter housing.
• Use needle-nose pliers to release any small hose clamp attached to the intake tube.
• Use a plastic trim removal tool to release any wiring clips from the tube.
• Remove the air intake tube and set it aside.

Step 3: Remove the Front Bank Ignition Coils

• The ignition coil is the small electrical part mounted directly over each spark plug.
• Use your fingers to press the connector lock tab and unplug each front ignition coil connector.
• Use a 10mm socket and 1/4-inch drive ratchet to remove each coil retaining bolt.
• Pull each coil straight up with a gentle twisting motion.
• Keep the coils in order so they go back in the same positions.

Step 4: Clean the Front Spark Plug Wells

• Use a compressed air blow gun to blow dirt out of each spark plug well before removing the plugs.
• Wear safety glasses while using compressed air.
• Dirt inside the engine causes damage.

Step 5: Remove the Front Spark Plugs

• Use a 5/8-inch spark plug socket, 6-inch extension, and 3/8-inch drive ratchet to loosen each front spark plug.
• A spark plug socket has a rubber insert or magnet that holds the plug so it does not fall.
• Turn counterclockwise slowly until the plug is loose, then remove it by hand with the extension.
• If a plug feels stuck, stop and work it back and forth gently.

Step 6: Install the Front Spark Plugs

• Place one new iridium spark plug into the 5/8-inch spark plug socket.
• Use the 6-inch extension by hand only to start threading the plug clockwise.
• Once the plug is fully hand-started, use a torque wrench and 5/8-inch spark plug socket to tighten it to Torque to 18 Nm (13 ft-lbs).
• Repeat for all three front plugs.
• Hand-starting prevents stripped threads.

Step 7: Reinstall the Front Ignition Coils

• Apply a small amount of dielectric grease inside each coil boot. Dielectric grease helps seal out moisture but does not conduct electricity.
• Push each ignition coil straight down onto its spark plug until it seats fully.
• Use a 10mm socket and inch-pound torque wrench to tighten each coil bolt to Torque to 10 Nm (89 in-lbs).
• Reconnect each ignition coil electrical connector until it clicks.

Step 8: Remove Upper Intake Manifold Connections

• The upper intake manifold is the large plastic air chamber on top of the engine that blocks access to the rear spark plugs.
• Use a plastic trim removal tool to detach wiring harness clips from the upper intake manifold.
• Use your fingers to unplug electrical connectors attached to the throttle body and nearby sensors.
• Use needle-nose pliers to release small hose clamps, then remove attached vacuum or breather hoses.
• Take a phone photo before disconnecting hoses so reassembly is easy.

Step 9: Remove the Throttle Body if Needed

• If the throttle body blocks intake manifold removal, use a 10mm socket to remove its mounting bolts.
• Remove the throttle body and old throttle body gasket.
• Do not spray cleaner directly into electronic throttle components during this repair.
• During reassembly, install a new throttle body gasket and tighten the throttle body bolts to Torque to 10 Nm (89 in-lbs).

Step 10: Remove the Upper Intake Manifold

• Use a 10mm socket, 6-inch extension, and 3/8-inch drive ratchet to remove the upper intake manifold bolts.
• Lift the upper intake manifold carefully away from the engine.
• Remove the old upper intake manifold gaskets.
• Cover the open intake ports with clean shop towels immediately.
• Never drop hardware into intake ports.

Step 11: Remove the Rear Bank Ignition Coils

• Use your fingers to unplug the rear ignition coil connectors.
• Use a 10mm socket, 3-inch extension, and 1/4-inch drive ratchet to remove the rear coil retaining bolts.
• Pull each rear coil straight up with a gentle twisting motion.
• Keep the rear coils in order.

Step 12: Clean the Rear Spark Plug Wells

• Use a compressed air blow gun to clean each rear spark plug well.
• Wear safety glasses and keep your face away from the plug wells.

Step 13: Remove the Rear Spark Plugs

• Use a 5/8-inch spark plug socket, 10-inch extension, 3/8-inch universal joint adapter, and 3/8-inch drive ratchet to remove the rear spark plugs.
• A universal joint adapter lets the socket bend slightly for tight spaces.
• Break each plug loose slowly, then spin it out by hand using the extension.

Step 14: Install the Rear Spark Plugs

• Place a new spark plug into the 5/8-inch spark plug socket.
• Use the 10-inch extension by hand to start the plug threads.
• After the plug is fully hand-started, use a torque wrench and 5/8-inch spark plug socket to tighten it to Torque to 18 Nm (13 ft-lbs).
• Repeat for all three rear plugs.

Step 15: Reinstall the Rear Ignition Coils

• Apply a small amount of dielectric grease inside each rear coil boot.
• Push each coil straight onto its spark plug.
• Use a 10mm socket and inch-pound torque wrench to tighten each coil bolt to Torque to 10 Nm (89 in-lbs).
• Reconnect each coil electrical connector until it clicks.

Step 16: Reinstall the Upper Intake Manifold

• Remove the shop towels from the intake ports.
• Install the new upper intake manifold gaskets into the manifold grooves.
• Set the upper intake manifold straight down into position.
• Use a 10mm socket to start all manifold bolts by hand first.
• Use a torque wrench to tighten the bolts evenly in a crisscross pattern to Torque to 10 Nm (89 in-lbs).

Step 17: Reconnect Hoses, Connectors, and Intake Tube

• Use your phone photo as a guide to reconnect all hoses and electrical connectors.
• Use needle-nose pliers to reinstall hose clamps in their original positions.
• Use a plastic trim removal tool to secure wiring clips back onto their brackets.
• Reinstall the air intake tube.
• Use an 8mm socket to tighten both intake tube clamps snugly.

Step 18: Reconnect the Battery and Reinstall the Cover

• Use a 10mm socket to reconnect the negative battery cable.
• Use a 10mm socket and torque wrench to tighten the battery terminal to Torque to 6 Nm (53 in-lbs).
• Press the engine cover straight down onto its rubber mounts.

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✅ After Repair

• ✅ Start the engine and let it idle for a few minutes.
• ✅ A slightly rough idle for the first few seconds can happen after the battery was disconnected.
• ✅ Listen for hissing noises, which can indicate an intake vacuum leak.
• ✅ Check that all electrical connectors and hoses are fully seated.
• ✅ If the check engine light comes on or flashes, shut the engine off and recheck coil connectors first.
• ✅ Road test your Traverse gently for 10-15 minutes and confirm smooth acceleration.

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💰 DIY vs Shop Cost

Shop Cost: $450-$750 (parts + labor)

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

You Save: $370-$570 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 2-3 hours.

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🎯 Ready to get started?

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