🔧 Seltos - Spark Plug Replacement

Replacing the spark plugs restores strong ignition, smooth idle, and good fuel economy. On your Seltos, the plugs sit under the ignition coils on top of the engine, so the job is mostly careful removal and reinstall with correct torque.

Difficulty Level: Intermediate | Estimated Time: 1.0-1.5 hours

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⚠️ Safety & Precautions

• ⚠️ Work on a fully cool engine to avoid burns and thread damage in the aluminum cylinder head.
• ⚠️ Keep dirt out of the spark plug holes; debris can damage the engine.
• ⚠️ Disconnect the negative battery terminal if you’re worried about bumping connectors or shorting tools.
• ⚠️ Do not pull on wiring—release connector locks and pull by the plug body.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 3/8" drive ratchet
• 3/8" drive 6" extension
• 5/8" spark plug socket
• Torque wrench (3/8" drive, 10–30 ft-lbs range)
• Trim removal tool
• Compressed air blow gun
• Dielectric grease
• Feeler gauge set
• 10mm wrench
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs (iridium, correct fit for your Seltos) - Qty: 4
• Ignition coil boot (optional, if any boot is torn/oil-soaked) - Qty: 0-4

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📋 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).
• If disconnecting the battery: use a 10mm wrench to remove the negative terminal and keep it from touching the post.
• Quick check: if your Seltos has the 1.6L turbo, there may be extra ducting/hoses near the top—move them gently as needed for access.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover (if equipped)

• Use a trim removal tool to pop the cover upward at the corners (most covers are press-fit grommets).
• If your cover uses fasteners, remove them with a 10mm socket.
• Lift straight up to avoid breaking grommets.

Step 2: Unplug the ignition coils

• Locate the four ignition coils on top of the engine (one per cylinder).
• Press the connector lock and unplug each coil connector by hand; use a trim removal tool gently if the lock is stubborn.

Step 3: Remove the ignition coils

• Remove each coil retaining bolt using a 10mm socket and 3/8" drive ratchet.
• Twist the coil slightly, then pull straight up to remove it.
• Put a tiny smear of dielectric grease inside each coil boot before reassembly (this helps prevent moisture and makes future removal easier).

Step 4: Clean the spark plug wells

• Wear safety glasses.
• Use a compressed air blow gun to blow out dirt from each spark plug well before removing the plug.
• This prevents grit from falling into the cylinder.

Step 5: Remove the old spark plugs

• Install the 5/8" spark plug socket on a 3/8" drive 6" extension and 3/8" drive ratchet.
• Turn counterclockwise to loosen, then remove the plug carefully.
• If a plug feels stuck, stop and re-tighten slightly, then loosen again (don’t force it).

Step 6: Check and prepare the new spark plugs

• Use a feeler gauge set to verify the plug gap matches the specification for the plug set you purchased for your Seltos.
• Do not apply anti-seize unless the plug manufacturer specifically requires it (most modern plated plugs do not).

Step 7: Install the new spark plugs

• Start each plug by hand using the 5/8" spark plug socket and extension (no ratchet at first) to avoid cross-threading.
• Once seated, tighten with a torque wrench: Torque to 20 Nm (15 ft-lbs).
• Hand-starting is the key to not stripping threads.

Step 8: Reinstall the ignition coils

• Push each coil straight down until fully seated on the plug.
• Install coil bolts with a 10mm socket, then snug with a torque wrench: Torque to 9 Nm (80 in-lbs).
• Reconnect each coil electrical connector until it clicks.

Step 9: Reinstall the engine cover

• Align the cover with the mounting pegs and press down firmly by hand.
• If removed, reconnect the negative battery cable using a 10mm wrench and tighten securely.

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✅ After Repair

• Start the engine and let it idle for 30–60 seconds; it should be smooth with no misfire shaking.
• If you have a check engine light or rough running, re-check that each coil connector is fully clicked in.
• Do a short test drive, then re-check for any warning lights.

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💰 DIY vs Shop Cost

Shop Cost: $250-$450 (parts + labor)

DIY Cost: $40-$140 (parts only)

You Save: $110-$410 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.0-1.5 hours.

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🎯 Ready to get started?

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