🔧 Explorer - Ignition Coil Replacement

Your Explorer uses coil-on-plug ignition coils (one coil per spark plug). A bad coil can cause misfires, rough running, and a flashing check-engine light. This job is straightforward on the front bank, but the rear bank is tighter and usually requires removing the upper intake manifold for access.

Difficulty Level: Intermediate | Estimated Time: 1.5-3.5 hours

Assumption: 3.5L NA V6 (transverse) with rear-bank access requiring upper intake manifold removal.

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⚠️ Safety & Precautions

• ⚠️ Work on a cool engine to avoid burns (intake and exhaust areas get very hot).
• ⚠️ Disconnect the negative battery cable to prevent accidental shorting while unplugging coils.
• ⚠️ Keep dirt out of the intake ports—cover openings immediately if the intake manifold comes off.
• ⚠️ Do not pull on wiring; release connector locks first to avoid breaking plugs.

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🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Nitrile gloves
• 1/4" drive ratchet
• 3/8" drive ratchet
• 1/4" drive extension set (3" and 6")
• 3/8" drive extension (6")
• 7mm socket
• 8mm socket
• 10mm socket
• 13mm socket
• Torx T20 screwdriver
• Flat trim tool
• Small pick tool
• Torque wrench (in-lb)
• Torque wrench (ft-lb)
• Telescoping magnetic pickup tool
• Shop vacuum
• Flashlight

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Ignition coil - Qty: 1 (or replace as needed)
• Upper intake manifold gasket set - Qty: 1 (recommended if upper intake is removed)
• Dielectric grease - Qty: 1 (optional but recommended)

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📋 Before You Begin

• Park on level ground, shift to Park, and set the parking brake.
• Open the hood and let the engine cool fully.
• Use a 10mm socket to disconnect the negative battery cable and tuck it aside so it can’t spring back.
• If you’re doing multiple coils, label connectors with tape so everything goes back to the same place.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover

• Pull up firmly on the engine cover to release the rubber grommets (it snaps on).
• Set it aside where it won’t get stepped on.

Step 2: Remove the air intake tube (for room)

• Use a 7mm socket to loosen the hose clamps at the air box and throttle body.
• Unplug any sensor connectors using a small pick tool to lift the lock tab (a lock tab is a small clip that prevents unplugging).
• Remove the intake tube and set it aside.

Step 3: Replace coils on the front bank (easier side)

• Identify the coil you’re replacing on the front side of the engine (closest to the radiator).
• Unplug the coil electrical connector using a small pick tool to release the lock, then pull the connector straight off.
• Use an 8mm socket with a 1/4" drive ratchet to remove the coil hold-down bolt.
• Twist the coil gently, then pull straight up to remove it.
• Tip: Don’t pry on the plastic coil body.
• Optional: apply a pea-sized amount of dielectric grease inside the new coil boot (dielectric grease helps prevent moisture and eases future removal).
• Push the new coil down until it fully seats on the spark plug.
• Install the hold-down bolt with an 8mm socket and torque wrench (in-lb): Torque to 71 in-lb (8 Nm).
• Reconnect the electrical connector until it clicks.

Step 4: Access the rear bank coils (upper intake manifold removal)

• Use a flat trim tool to release any wiring harness clips attached to the upper intake area.
• Unplug the throttle body connector and any nearby vacuum/EVAP connectors using a small pick tool.
• Remove the throttle body fasteners using an 8mm socket (or 10mm socket depending on hardware), and move it aside if slack allows.
• Disconnect vacuum/PCV hoses carefully; twist hoses to break them free instead of yanking.
• Use an 8mm socket and 1/4" drive extensions to remove the upper intake manifold bolts.
• Lift the upper intake manifold straight up and out.
• Immediately place clean shop towels over the intake openings to prevent anything from falling in.
• Tip: A dropped bolt in an intake port is a big problem.

Step 5: Replace coils on the rear bank

• Use a shop vacuum to clean loose dirt around the coil bases before removal.
• Unplug each coil connector using a small pick tool.
• Remove each coil hold-down bolt using an 8mm socket.
• Twist and pull the coil straight up to remove it.
• Install the new coil(s), pushing down until fully seated.
• Install hold-down bolts and use a torque wrench (in-lb): Torque to 71 in-lb (8 Nm).
• Reconnect coil connectors until they click.

Step 6: Reinstall the upper intake manifold

• Remove the shop towels from the intake openings.
• Replace the intake manifold gaskets if removed; ensure they sit flat and aren’t pinched.
• Set the upper intake manifold in place carefully and start all bolts by hand to avoid cross-threading.
• Tighten bolts evenly in a crisscross pattern using an 8mm socket, then use a torque wrench (in-lb): Torque to 89 in-lb (10 Nm).
• Reconnect all vacuum/PCV hoses and electrical connectors.

Step 7: Reassemble intake tube and engine cover

• Reinstall the air intake tube and tighten clamps with a 7mm socket.
• Reconnect any sensor connectors.
• Snap the engine cover back into place.

Step 8: Reconnect the battery

• Reconnect the negative battery cable using a 10mm socket.

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✅ After Repair

• Start the engine and let it idle for 1–2 minutes. It should run smooth with no shaking.
• Listen for hissing (a vacuum leak). If you hear one, re-check intake hoses and manifold seating.
• If the check-engine light stays on, it may need a code clear after the fix (some lights clear on their own after a few drive cycles).
• Road test gently, then recheck for any loose clamps or disconnected plugs.

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💰 DIY vs Shop Cost

Shop Cost: $350-$900 (parts + labor, depends on how many coils and rear-bank labor)

DIY Cost: $45-$450 (parts only, depends on 1 coil vs multiple)

You Save: $200-$500+ by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.5-3.0 hours.

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🎯 Ready to get started?

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