🔧 Land Cruiser - Spark Plug Replacement

Your Land Cruiser uses coil-on-plug ignition (one ignition coil per spark plug). Replacing the plugs restores smooth idle, power, and fuel economy—especially if you’re due by mileage or you’re chasing a misfire.

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

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⚠️ Safety & Precautions

• 🔥 Work on a completely cool engine; spark plugs in a hot aluminum head can strip threads.
• ⚡ Keep the key far away; do not crank with coils unplugged.
• 🧼 Blow dirt away before removing coils/plugs to prevent debris falling into the cylinders.
• 🔌 If you disconnect the battery, you may lose radio presets and clock settings.
• 🧯 Do not use anti-seize on Toyota iridium plugs unless the plug maker specifically requires it; it can cause over-tightening.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 10mm wrench
• 3/8" drive ratchet
• 3/8" drive torque wrench (5–30 ft-lbs range)
• 6" extension
• 12" extension
• 5/8" spark plug socket
• Pick tool
• Plastic trim removal tool
• Compressed air nozzle
• Shop vacuum
• Flashlight
• Dielectric grease
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Iridium spark plugs (correct fit for Land Cruiser 5.7L) - Qty: 8
• Upper intake plenum gasket set - Qty: 1 Only if plenum is removed
• Throttle body gasket - Qty: 1 Only if throttle body is removed

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📋 Before You Begin

• Park on level ground, shift to Park, and set the parking brake.
• Open the hood and remove any loose jewelry or clothing that can snag.
• If you choose to disconnect the battery: use a 10mm wrench to remove the negative terminal and isolate it so it can’t spring back.
• Plan to replace plugs one cylinder at a time so nothing gets mixed up.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover and open up access

• Pull up/remove the top engine cover using a plastic trim removal tool if needed.
• Use a flashlight to locate the ignition coils (they sit directly on top of the spark plugs).

Step 2: Decide your access path (two common ways)

• Path A (preferred if you have room): Replace plugs with only coil removal.
• Path B (if rear plugs are too tight to reach): Remove the upper intake plenum for more room. More work, but easier plug access.

Step 3: Unplug one ignition coil

• Press the connector lock and unplug the coil electrical connector using a pick tool gently if it’s stubborn.
• An ignition coil is the module that creates spark for that plug.

Step 4: Remove the ignition coil

• Remove the coil hold-down bolt using a 10mm socket and 3/8" drive ratchet.
• Twist the coil slightly, then pull it straight up and out.
• Put a tiny smear of dielectric grease inside the rubber boot (optional but helpful). Use very little.

Step 5: Clean the spark plug well

• Blow compressed air down into the spark plug well using a compressed air nozzle.
• If there’s loose debris, use a shop vacuum to remove it.

Step 6: Remove the old spark plug

• Install a 5/8" spark plug socket with a 6" extension and 3/8" drive ratchet.
• Break the plug loose, then spin it out slowly.
• If it feels gritty or binds, stop and tighten slightly, then loosen again. Go slow to protect threads.

Step 7: Install the new spark plug (do not cross-thread)

• Place the new plug into the 5/8" spark plug socket.
• Lower it into the well using the extension only and thread it by hand (no ratchet at first).
• Once it seats by hand, torque it with a 3/8" drive torque wrench: Torque to 18 Nm (13 ft-lbs).
• Do not re-gap iridium plugs; they’re normally pre-set and the tip is easy to damage.

Step 8: Reinstall the ignition coil

• Push the coil straight down until fully seated.
• Install the coil bolt using a 10mm socket and 3/8" drive torque wrench: Torque to 9 Nm (80 in-lbs).
• Reconnect the electrical connector until it clicks.

Step 9: Repeat for all 8 cylinders

• Repeat Steps 3–8 for each coil/plug, moving one cylinder at a time.
• Use a 12" extension where access is deeper/tighter.

Step 10 (Only if needed): Upper intake plenum removal for access (Path B)

• If you cannot physically get a straight shot to the rear plugs, stop and remove the upper intake plenum.
• Use a 10mm socket, 3/8" drive ratchet, and plastic trim removal tool to remove intake tube/clamps and plenum fasteners as required.
• Replace any removed gaskets with the upper intake plenum gasket set before reassembly.
• After reassembly, re-check that every vacuum/air hose and every electrical connector is fully seated.

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✅ After Repair

• If you disconnected the battery, reconnect it using a 10mm wrench and make sure the terminal is tight.
• Start the engine and listen for a smooth idle; it should not shake or misfire.
• Check for a warning light. If you have one, re-check coil connectors and coil bolts.
• Take a short test drive and confirm normal power and no flashing check-engine light.

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💰 DIY vs Shop Cost

Shop Cost: $450-$900 (parts + labor)

DIY Cost: $90-$220 (parts only)

You Save: $360-$680 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?

HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.