🔧 RDX - Ignition Coil Replacement

Ignition coils create the high voltage that fires your spark plugs. On your RDX V6, the front bank coils are easy to reach, but the rear bank sits under the upper intake (plenum), so you’ll remove that to access the last three coils.

Difficulty Level: Intermediate | Estimated Time: 2.0-4.0 hours

Assumption: Torque specs listed are common J35 V6 values; verify if you have a factory spec source.

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⚠️ Safety & Precautions

• ⚠️ Work on a cool engine to avoid burns.
• ⚠️ Disconnect the negative battery cable to prevent accidental shorting.
• ⚠️ Keep dirt out of the intake ports; cover openings with clean shop towels.
• ⚠️ Don’t pull on wires—press the connector tab and pull the plug body.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 12mm socket
• 8mm socket
• 3/8" drive ratchet
• 3/8" drive torque wrench (5-60 Nm range)
• 3/8" drive extension set (3", 6", 10")
• Flathead screwdriver
• Needle-nose pliers
• Trim clip removal tool
• Pick tool
• Magnetic pickup tool
• Flashlight
• Shop towels
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Ignition coil - Qty: 6 (recommended replace all six)
• Upper intake manifold (plenum) gasket set - Qty: 1
• Throttle body gasket - Qty: 1
• Dielectric grease - Qty: 1

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📋 Before You Begin

• Park on level ground and set the parking brake.
• Open the hood and remove any loose jewelry (rings/watches).
• Use a labeling method (masking tape + marker) for hoses/connectors on the intake.
• Disconnect the battery: use a 10mm socket to remove the negative terminal and tuck it aside.

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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 it (some versions use rubber grommets).
• Set it aside.

Step 2: Replace the front bank coils (easy side)

• Locate the three coils at the front of the engine (closest to the radiator).
• Press the tab and unplug the coil electrical connector.
• Use a 10mm socket and 3/8" ratchet to remove the coil hold-down bolt.
• Twist the coil gently and pull straight up to remove it.
• Put a tiny smear of dielectric grease inside the new coil boot. Less is more.
• Install the new coil fully onto the spark plug, reinstall the bolt, and Torque to 12 Nm (9 ft-lbs).
• Reconnect the electrical connector (you should feel/hear a click).
• Repeat for the other two front coils.

Step 3: Remove the air intake ducting

• Use a flathead screwdriver (or 8mm socket) to loosen the intake hose clamps.
• Unclip/unplug any sensor connector on the intake tube (press tab, pull gently).
• Remove the intake tube and set it aside.

Step 4: Prep the upper intake (plenum) for removal

• Unplug the throttle body connector and any nearby connectors in your way.
• Use needle-nose pliers to slide hose clamps back, then remove vacuum/PCV/EVAP hoses connected to the plenum.
• Label each hose/connector with tape so it goes back to the same spot.

Step 5: Remove the throttle body from the plenum

• Use a 10mm socket and 3/8" ratchet to remove the throttle body mounting bolts.
• Carefully pull the throttle body away and set it aside without stressing hoses (some setups have coolant lines—don’t force them).
• Remove the old throttle body gasket and plan to install a new one.
• When reinstalling later, Torque to 12 Nm (9 ft-lbs).

Step 6: Remove the upper intake (plenum)

• Use a 12mm socket, extensions, and 3/8" ratchet to remove the plenum mounting bolts/nuts.
• Lift the plenum straight up and out. If it sticks, gently rock it—don’t pry hard on sealing surfaces.
• Immediately place shop towels in the intake openings to prevent dropping anything inside.
• Remove the old plenum gaskets and keep the sealing surfaces clean.
• When reinstalling later, tighten evenly and Torque to 22 Nm (16 ft-lbs).

Step 7: Replace the rear bank coils (under the plenum)

• Locate the three rear coils (closest to the firewall).
• Unplug each coil connector (press tab, pull gently).
• Use a 10mm socket to remove each coil bolt.
• Remove and replace one coil at a time to avoid mixing anything up.
• Install bolts and Torque to 12 Nm (9 ft-lbs).
• Reconnect the electrical connectors.

Step 8: Reinstall the plenum with new gaskets

• Remove the shop towels from the intake openings.
• Install the new plenum gaskets in their grooves/seats.
• Set the plenum in place carefully, making sure nothing is pinched underneath.
• Hand-start all bolts/nuts, then tighten evenly in a crisscross pattern.
• Torque to 22 Nm (16 ft-lbs).

Step 9: Reinstall the throttle body with a new gasket

• Install the new throttle body gasket.
• Reinstall the throttle body bolts using a 10mm socket.
• Torque to 12 Nm (9 ft-lbs).
• Reconnect the throttle body electrical connector.

Step 10: Reinstall hoses, connectors, and the intake duct

• Reconnect all vacuum/PCV/EVAP hoses to their labeled locations.
• Reinstall the intake tube and tighten clamps using a flathead screwdriver or 8mm socket.
• Double-check that every connector is clicked in and every hose clamp is secure.

Step 11: Reconnect the battery and reinstall the engine cover

• Reconnect the negative battery terminal using a 10mm socket.
• Reinstall the engine cover.

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✅ After Repair

• Start the engine and let it idle for 2-3 minutes. Expect a slightly rough idle for a short moment if the throttle learned position resets.
• Listen for hissing (vacuum leak) around the plenum and intake tube.
• If you had a check-engine light, use a scan tool to clear codes and confirm misfires are gone.
• Take a short test drive and re-check for warning lights.

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💰 DIY vs Shop Cost

Shop Cost: ₹12,000-₹28,000 (parts + labor)

DIY Cost: ₹6,000-₹18,000 (parts only)

You Save: ₹6,000-₹10,000 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 2.0-4.0 hours.

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🎯 Ready to get started?

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