🔧 Traverse - Spark Plug Replacement

This is an intermediate job, mainly because the upper intake manifold blocks the rear three spark plugs. Replace all six plugs together. Work only on a completely cold engine because removing plugs from hot aluminum cylinder heads can damage the threads. parts.chevrolet.com

Difficulty Level: Intermediate | Estimated Time: 3-4 hours

Assumption: These instructions cover the stock 3.6L V6 installation. Verify fastener torque against current GM service information if your replacement gasket or plug manufacturer specifies otherwise.

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⚠️ Safety & Precautions

• ⚠️ Let the engine cool for several hours before removing any spark plug.
• ⚠️ Disconnect the negative battery cable before unplugging the throttle body or ignition coils.
• ⚠️ Never allow dirt, tools, bolts, or gasket pieces into an open intake port.
• ⚠️ Cover every intake opening immediately after lifting the manifold.
• ⚠️ Wear eye protection when blowing debris from the spark plug wells.
• ⚠️ Never force a spark plug. The cylinder heads are aluminum and easily damaged.
• ⚠️ Don’t apply anti-seize unless the spark plug manufacturer specifically requires it.

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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
• 7mm socket
• 8mm socket
• 10mm socket
• 15mm socket
• 14mm thin-wall spark plug socket
• 3-inch extension
• 6-inch extension
• 10-inch extension
• 3/8-inch drive universal joint
• Inch-pound torque wrench rated 50-150 in-lbs
• Foot-pound torque wrench rated 10-50 ft-lbs
• Torx T30 bit socket
• Flat-blade screwdriver
• 90-degree pick tool
• Spark plug gap gauge marked in thousandths
• Compressed-air blow gun rated below 30 psi
• Shop vacuum with narrow nozzle
• Plastic trim removal tool
• Clean shop towels
• Masking tape and permanent marker
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Vehicle-matched iridium spark plugs - Qty: 6
• Upper intake manifold gasket set - Qty: 1
• Throttle-body gasket - Qty: 1 if the throttle body is removed
• Dielectric ignition grease - Qty: 1 small tube

Replace all six plugs. GM also advises replacing the complete set during scheduled service rather than mixing old and new plugs. parts.chevrolet.com

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📋 Before You Begin

• Park your Traverse on level ground, select Park, and apply the parking brake.
• Open the hood and allow the engine to become completely cold.
• Use masking tape and a permanent marker to label hoses and connectors before disconnecting them.
• Keep the key away from the vehicle so nobody accidentally switches the ignition on.
• Don’t change the gap on fine-wire iridium plugs unless their manufacturer explicitly permits it. GM warns that bending an OE iridium electrode can damage the plug. parts.chevrolet.com

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Disconnect the battery

• Use a 10mm socket and 1/4-inch drive ratchet to loosen the negative battery terminal.
• Lift the negative cable from the terminal and position it where it cannot spring back.
• Wait at least two minutes before disconnecting engine electrical connectors.

Step 2: Remove the engine cover

• Remove the oil-filler cap by hand if it passes through the engine cover.
• Grip the cover near its mounting points and pull straight upward to release its rubber retainers.
• Reinstall the oil cap temporarily so nothing enters the engine.

Step 3: Remove the air-intake duct

• Use a flat-blade screwdriver or appropriate socket to loosen the duct clamps.
• Release the breather hose with the 90-degree pick tool, taking care not to crack the plastic fitting.
• Unplug any intake sensor connector by releasing its lock with the plastic trim removal tool.
• Remove the duct between the air-filter housing and throttle body.

Step 4: Disconnect upper-manifold connections

• Use masking tape and a permanent marker to identify every hose and connector.
• Disconnect the throttle-body connector, manifold pressure sensor connector, purge line, brake-booster vacuum hose, and other attached wiring retainers as equipped.
• Use the 90-degree pick tool only to lift connector locks. Don’t pull on the wires.
• Move the wiring harness aside without stretching it.

Step 5: Remove the upper intake manifold

• Use the correctly fitting 8mm socket, 10mm socket, or Torx T30 bit socket to remove the manifold fasteners and brackets.
• Keep each fastener arranged in removal order because lengths may differ.
• Check all sides of the manifold for hidden hoses, connectors, and brackets before lifting it.
• Lift the manifold straight up. Don’t pry against its plastic sealing surfaces.
• Immediately place clean shop towels over every exposed intake port.
• Remove the old manifold seals and clean the sealing grooves with clean shop towels. Don’t use metal scrapers.
• Count every intake opening before moving on.

Step 6: Remove the ignition coils

• Use a plastic trim removal tool to release each coil connector lock.
• Press the connector tab and unplug each ignition coil.
• Use a 10mm socket and 1/4-inch drive ratchet to remove each coil retaining bolt.
• Twist each coil gently, then pull it straight upward.
• Keep the coils organized by cylinder so any unusual wear remains traceable.

Step 7: Clean the spark plug wells

• Use the shop vacuum with narrow nozzle to remove loose dirt around each plug.
• Wear safety glasses and use the compressed-air blow gun below 30 psi to clear remaining debris.
• Inspect each well for engine oil or coolant before removing the plug.
• If a well contains oil, repair the leaking tube seal before installing new plugs.

Step 8: Remove the old spark plugs

• Fit the 14mm thin-wall spark plug socket to the 6-inch or 10-inch extension and 3/8-inch drive ratchet.
• Break each plug loose carefully, then turn it out without side-loading the socket.
• If a plug becomes unusually tight, stop. Turn it slightly inward, then outward again rather than forcing it.
• Compare the six removed plugs for oil deposits, heavy fuel fouling, damaged porcelain, or one plug that looks different.

Step 9: Inspect the new spark plugs

• Confirm that all six plugs have the same application and reach.
• Use the spark plug gap gauge only to verify the supplied gap without levering against the fine-wire electrode.
• Replace any plug with cracked porcelain, damaged threads, or an incorrect gap that the manufacturer says not to adjust.
• Keep the plug threads clean and dry. Anti-seize changes the clamping force and can lead to overtightening.

Step 10: Install the new spark plugs

• Place one plug in the 14mm thin-wall spark plug socket and attach only the extension.
• Lower it straight into the well and thread it clockwise by hand through the extension.
• The plug should turn several full revolutions easily. If it doesn’t, back it out and start again.
• Use the foot-pound torque wrench to tighten each plug to 18 Nm (13 ft-lbs).
• Don’t add an extra pull after the torque wrench clicks. Aluminum threads remember mistakes.

Step 11: Reinstall the ignition coils

• Inspect each coil boot for cracks, carbon tracks, or torn rubber.
• Apply a very small film of dielectric grease inside the end of each boot. Keep grease off the plug threads and metal terminal.
• Push each coil straight onto its plug until fully seated.
• Install the coil bolts with the 10mm socket.
• Use the inch-pound torque wrench and tighten the coil bolts to 10 Nm (89 in-lbs).
• Reconnect each coil connector and fully seat its lock.

Step 12: Reinstall the upper intake manifold

• Use clean hands to install the new upper-manifold seals into their grooves.
• Remove every shop towel from the intake ports and count them before lowering the manifold.
• Check that no wires or hoses are trapped underneath.
• Lower the manifold squarely onto the engine without disturbing the seals.
• Start every fastener by hand, then snug them gradually from the center outward using the correct socket.
• Use the inch-pound torque wrench and tighten the upper-manifold fasteners evenly to 10 Nm (89 in-lbs).
• If a fastener design or service label specifies a staged sequence, follow that identification instead.

Step 13: Reconnect hoses and wiring

• Reconnect the throttle body, sensors, purge line, brake-booster hose, breather hose, and wiring retainers.
• Use your masking-tape labels to verify that every connection has been restored.
• Pull lightly on each quick-connect hose to confirm it has locked.

Step 14: Reinstall the intake duct and engine cover

• Install the air-intake duct and fully seat both ends before tightening the clamps with the flat-blade screwdriver or appropriate socket.
• Reconnect the intake sensor and breather hose.
• Remove the oil cap, align the engine cover, and press it onto its retainers.
• Reinstall the oil cap by hand.

Step 15: Reconnect the battery

• Place the negative cable onto the battery terminal.
• Use the 10mm socket and tighten it until secure without crushing or twisting the terminal.
• Check the engine compartment for tools, loose fasteners, and disconnected hoses before starting.

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✅ After Repair

• Switch the ignition on for several seconds, then start the engine without pressing the accelerator.
• The first start may take slightly longer after the battery has been disconnected.
• Listen for a loud hiss or unusually high idle, which can indicate an intake hose or manifold seal leak.
• Confirm that the check-engine light doesn’t flash. A flashing light indicates an active misfire, so shut the engine off and recheck the coils and connectors.
• Let the engine idle until it runs smoothly, then take a short test drive.
• Recheck the intake duct and visible vacuum connections after the test drive.
• Reset the clock and automatic window functions if they lost their settings.

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💰 DIY vs Shop Cost

Shop Cost: ₹35,000-₹65,000 equivalent, depending on imported parts and local labor

DIY Cost: ₹9,000-₹20,000 equivalent for plugs, gaskets, and consumables

You Save: Approximately ₹20,000-₹45,000 by doing it yourself!

Labor varies widely in Sonīpat because this U.S.-market Traverse may require imported parts. The repair generally occupies a shop for approximately 2.5-3.5 hours.

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