How to Replace Spark Plugs on a 2021 Honda Passport 3.5L V6 (Front & Rear Bank)
Step-by-step DIY guide with tools, parts, intake manifold removal tips, and torque specs for 2019, 2020, 2021, 2022, 2023
How to Replace Spark Plugs on a 2021 Honda Passport 3.5L V6 (Front & Rear Bank)
Step-by-step DIY guide with tools, parts, intake manifold removal tips, and torque specs for 2019, 2020, 2021, 2022, 2023
🔧 Passport - Spark Plug Replacement
On your Passport’s 3.5L V6, there are 6 spark plugs (3 in the front bank and 3 in the rear bank). The front bank is easy to reach, but the rear bank typically requires removing the upper intake manifold to access the coils and plugs safely.
Difficulty Level: Intermediate | Estimated Time: 2-4 hours
⚠️ Safety & Precautions
- ⚠️ Work on a cold engine to avoid burns and stripped threads.
- ⚠️ Disconnect the negative battery cable before unplugging coils/sensors.
- ⚠️ Keep dirt out of the intake ports; cover openings immediately.
- ⚠️ Do not over-tighten spark plugs; aluminum heads strip easily.
🔧 Required Tools
You'll need the following tools for this repair:
- Safety glasses
- Nitrile gloves
- 10mm socket
- 12mm socket
- 14mm socket
- 3/8" drive ratchet
- 3/8" drive torque wrench (10-80 N·m range)
- 6" extension (3/8" drive)
- 12" extension (3/8" drive)
- 3/8" universal joint adapter
- 5/8" spark plug socket (rubber insert)
- Flathead screwdriver
- Needle-nose pliers
- Trim clip remover
- Compressed air blow gun
- Shop towels
- Painter’s tape and marker
- Magnetic pickup tool
🔩 Required Parts
HowToo sells all the parts you need for this repair:
- Iridium spark plugs (OE type) - Qty: 6
- Upper intake manifold gasket set - Qty: 1
- Throttle body gasket - Qty: 1
- Dielectric grease (for coil boots) - Qty: 1
📋 Before You Begin
- Park on level ground, shift to Park, and set the parking brake.
- Let the engine cool completely (at least 1 hour after driving).
- Disconnect the battery: use a 10mm socket to remove the negative terminal and set it aside.
- Use painter’s tape and marker to label hoses/connectors you remove. This prevents mix-ups.
- A torque wrench sets bolt tightness accurately.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Remove the engine cover
- Pull up on the plastic engine cover to release it from the rubber grommets (use both hands).
- Set it aside.
Step 2: Remove the air intake duct
- Use a flathead screwdriver to loosen the hose clamps at the air box and throttle body.
- Unclip/remove any attached breather hose(s) using needle-nose pliers.
- Lift out the intake duct and set it aside.
Step 3: Replace the front bank spark plugs (front 3 cylinders)
- Unplug each ignition coil connector by pressing the tab (use a trim clip remover gently if needed).
- Remove each coil hold-down bolt using a 10mm socket.
- Twist the coil boot slightly, then pull the coil straight out.
- Blow out debris around each plug well using compressed air blow gun.
- Remove the spark plug using a 5/8" spark plug socket, 6" extension, and 3/8" ratchet.
- Install the new plug by hand first using the spark plug socket and extension (no ratchet) to prevent cross-threading.
- Tighten with a torque wrench: Torque to 18 N·m (13 ft-lbs).
- Add a small amount of dielectric grease inside the coil boot, then reinstall the coil.
- Reinstall coil bolt: Torque to 12 N·m (9 ft-lbs).
Step 4: Remove the throttle body from the intake (for rear bank access)
- Unplug the throttle body electrical connector (press the tab and pull straight back).
- Remove the throttle body mounting fasteners using a 10mm socket.
- Carefully pull the throttle body forward and set it aside with shop towels under it.
- Remove and discard the old throttle body gasket.
- Don’t pry on the throttle plate.
Step 5: Remove the upper intake manifold (rear bank access)
- Label and disconnect vacuum/EVAP hoses using needle-nose pliers as needed.
- Disconnect any remaining connectors attached to the upper intake (use a trim clip remover gently on stubborn clips).
- Remove the upper intake manifold bolts using a 12mm socket with a 3/8" ratchet and extensions.
- Lift the upper intake manifold straight up and off.
- Immediately cover the exposed intake ports with clean shop towels.
- Remove and discard the old upper intake manifold gaskets.
Step 6: Replace the rear bank spark plugs (rear 3 cylinders)
- Remove coil connectors and coil bolts using a 10mm socket.
- Pull coils out, then blow out each plug well using compressed air blow gun.
- Remove each spark plug using a 5/8" spark plug socket, 12" extension, and 3/8" universal joint adapter.
- Hand-thread the new plug in first, then torque: Torque to 18 N·m (13 ft-lbs).
- Reinstall coils and torque coil bolts: Torque to 12 N·m (9 ft-lbs).
- Reconnect all coil electrical connectors until they click.
Step 7: Reinstall the upper intake manifold
- Remove the shop towels from the intake ports (double-check nothing fell in).
- Install the new upper intake manifold gaskets in their grooves.
- Set the upper intake manifold back in place.
- Start all bolts by hand, then tighten evenly in a crisscross pattern using a 12mm socket.
- Final tighten with a torque wrench: Torque to 22 N·m (16 ft-lbs).
- Reconnect all hoses/connectors you labeled.
Step 8: Reinstall the throttle body and intake duct
- Install the new throttle body gasket.
- Reinstall the throttle body fasteners using a 10mm socket, then torque: Torque to 12 N·m (9 ft-lbs).
- Reconnect the throttle body electrical connector.
- Reinstall the air intake duct and tighten clamps with a flathead screwdriver.
Step 9: Reconnect battery and reinstall engine cover
- Reconnect the negative battery terminal using a 10mm socket.
- Press the engine cover back onto its grommets.
✅ After Repair
- Start the engine and let it idle. Listen for vacuum leaks (hissing) around the intake.
- If the idle hunts or is high after reconnecting the battery, perform an idle relearn: warm the engine fully, then let it idle for 5 minutes with all accessories off.
- Test drive 10-15 minutes and confirm there’s no check engine light.
- Recheck that all intake clamps/hoses are secure once back home.
💰 DIY vs Shop Cost
Shop Cost: $450-$750 (parts + labor)
DIY Cost: $90-$220 (parts only)
You Save: $230-$660 by doing it yourself!
Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 2-4 hours.
🎯 Ready to get started?
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