🔧 Pilot - Spark Plug Replacement

On your Pilot, the spark plugs fire the air/fuel mix. Worn plugs can cause misfires, rough idle, poor fuel economy, and hard starts. This job replaces all 6 plugs; the rear bank requires removing the upper intake manifold (plenum) to reach the coils and plugs.

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

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⚠️ Safety & Precautions

• 🛑 Work on a cool engine to avoid burns and stripped threads.
• 🧯 Keep fuel/vapor sources away from sparks and open flames.
• 🔌 Disconnect the negative battery cable to prevent accidental shorting.
• 🧼 Keep dirt out of the intake; cover openings with clean shop towels.
• 🧴 Don’t use anti-seize on Honda plug threads unless the plug maker specifically says to (it can change torque).

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🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Nitrile gloves
• 10mm socket
• 12mm socket
• 3/8" drive ratchet
• 3/8" drive extension set
• 3/8" drive wobble extension
• Torque wrench (3/8" drive, 10–30 ft-lbs range)
• 14mm thin-wall spark plug socket (3/8" drive)
• Flathead screwdriver
• Trim clip tool
• Needle-nose pliers
• Small pick tool
• Compressed air blow gun
• Shop towels
• Paint marker

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs (OEM-style iridium) - Qty: 6
• Upper intake manifold gasket set - Qty: 1
• Throttle body gasket - Qty: 1
• Dielectric grease - Qty: 1

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📋 Before You Begin

• 🅿️ Park on level ground, shift to Park, and set the parking brake.
• 🔑 Make sure the ignition is OFF and the key is away from the vehicle.
• 🔌 Disconnect the negative battery terminal using a 10mm socket.
• 🏷️ Use a paint marker to mark vacuum hoses/connectors so they go back to the same spots.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover

• Pull up on the plastic engine cover to release the grommets (no tools or use a trim clip tool if it’s tight).

Step 2: Replace the front bank spark plugs (closest to radiator)

• Unplug each ignition coil connector by lifting the lock with a small pick tool, then press the tab and pull the connector off.
• Remove each ignition coil hold-down bolt with a 10mm socket, then pull the coil straight out.
• Blow out the spark plug well using a compressed air blow gun so dirt doesn’t fall into the cylinder.
• Remove the spark plug using a 14mm thin-wall spark plug socket with a 3/8" ratchet and 3/8" extension.
• Install the new plug by hand first using the spark plug socket and extension (no ratchet at first). Hand-threading prevents cross-threading.
• Tighten with a torque wrench: Torque to 18 N·m (13 ft-lbs).
• Apply a small dab of dielectric grease inside the coil boot.
• Reinstall the coil and bolt with a 10mm socket, then tighten with a torque wrench: Torque to 12 N·m (9 ft-lbs).
• Reconnect the coil connector until it clicks.

Step 3: Remove the air intake duct (to access the rear bank area)

• Loosen the intake hose clamps with a flathead screwdriver.
• Disconnect any breather/vacuum hoses using needle-nose pliers for the clamps.
• Lift the duct out and set it aside.

Step 4: Remove the throttle body from the upper intake manifold

• Unplug the throttle body electrical connector (release the tab; use a small pick tool if needed).
• Remove the throttle body fasteners with a 10mm socket.
• Pull the throttle body straight off and remove the old gasket.
• Cover the opening with a shop towel.
• When reinstalling later, tighten with a torque wrench: Torque to 12 N·m (9 ft-lbs).

Step 5: Remove the upper intake manifold (plenum)

• Disconnect vacuum lines and connectors from the plenum (mark them first using a paint marker).
• Remove the plenum mounting bolts/nuts using a 10mm socket and 12mm socket with a 3/8" ratchet and wobble extension.
• Lift the plenum off carefully and remove the old gaskets.
• Cover the lower intake openings with shop towels immediately.
• When reinstalling later, tighten the plenum mounting fasteners evenly with a torque wrench: Torque to 22 N·m (16 ft-lbs).

Step 6: Replace the rear bank spark plugs (closest to firewall)

• Unplug ignition coils (use a small pick tool for the lock if needed).
• Remove coil bolts with a 10mm socket and pull coils out.
• Blow out the plug wells using a compressed air blow gun.
• Remove each plug with a 14mm thin-wall spark plug socket, extension, and 3/8" ratchet.
• Install new plugs by hand first, then tighten with a torque wrench: Torque to 18 N·m (13 ft-lbs).
• Add a small dab of dielectric grease inside each coil boot.
• Reinstall coils and tighten coil bolts with a torque wrench: Torque to 12 N·m (9 ft-lbs).
• Reconnect coil connectors until they click.

Step 7: Reinstall the upper intake manifold and throttle body

• Remove shop towels from the intake runners.
• Install new upper intake manifold gaskets (make sure they sit flat).
• Set the plenum in place and start all fasteners by hand.
• Tighten evenly with a torque wrench: Torque to 22 N·m (16 ft-lbs).
• Install a new throttle body gasket and reinstall the throttle body using a 10mm socket.
• Tighten throttle body fasteners with a torque wrench: Torque to 12 N·m (9 ft-lbs).
• Reconnect the throttle body connector and all vacuum hoses.

Step 8: Reinstall the intake duct and engine cover

• Reinstall the intake duct and tighten clamps with a flathead screwdriver.
• Reconnect any hoses using needle-nose pliers for the clamps.
• Reinstall the engine cover by pressing it onto the grommets.
• Reconnect the negative battery cable using a 10mm socket.

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✅ After Repair

• 🔍 Start the engine and listen for smooth idle. Any shaking usually means a coil connector or vacuum hose is loose.
• 🧪 Check for intake air leaks: a loud hissing sound or high idle can indicate a hose left off.
• 🧠 Idle relearn (after battery disconnect): let the engine fully warm up, turn off all accessories, then let it idle in Park for about 5 minutes.
• 🛠️ If the check engine light comes on, stop and recheck coil connectors and vacuum lines before driving.

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💰 DIY vs Shop Cost

Shop Cost: $400-$800 (parts + labor)

DIY Cost: $80-$200 (parts only)

You Save: $320-$600 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?

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