🔧 Spark Plugs - Replacement

The spark plugs on your Land Cruiser sit under the intake plenum, so this job is more involved than a basic tune-up. You’ll remove the upper intake parts, replace all eight plugs, and reassemble everything carefully to avoid vacuum leaks or misfires.

Difficulty Level: Intermediate | Estimated Time: 3-5 hours

---

⚠️ Safety & Precautions

• Work on a cold engine only. The intake and exhaust area can stay hot for a long time.
• Disconnect the negative battery cable before removing intake components.
• Keep dirt out of the intake ports at all times. Cover any open ports immediately.
• Do not overtighten the new plugs. The aluminum cylinder heads can be damaged.
• Use a spark plug socket with a rubber insert or magnet to avoid dropping plugs into the wells.

---

🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 12mm socket
• 14mm socket
• 6mm socket
• 3/8-inch ratchet
• 3-inch extension
• 6-inch extension
• 10-inch extension
• Universal joint socket adapter
• 10mm wrench
• Spark plug socket, 5/8-inch
• Torque wrench
• Flat blade trim tool
• Needle-nose pliers
• Dielectric grease
• Anti-seize compound
• Fender cover
• Safety glasses
• Mechanic gloves

---

🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Spark plugs, iridium - Qty: 8
• Intake manifold gasket set - Qty: 1
• Throttle body gasket - Qty: 1
• Air cleaner duct clamps or hose clamps, if damaged - Qty: 1 set

---

📋 Before You Begin

• Park on level ground and set the parking brake.
• Let the engine cool completely.
• Disconnect the negative battery terminal with a 10mm wrench.
• Label vacuum hoses and connectors as you remove them.
• Take photos before unplugging anything.

---

🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover and intake duct

• Use a 10mm socket to remove the engine cover fasteners, then lift the cover off.
• Use a flat blade trim tool to loosen the air intake duct clips if needed.
• Remove the intake duct from the throttle body and air box.

Step 2: Disconnect the throttle body and intake components

• Use a 10mm socket to remove the throttle body mounting bolts if the ducting or intake tube blocks access.
• Unplug the throttle body connector by pressing the lock tab first.
• Remove any breather hoses and vacuum lines attached to the intake assembly.

Step 3: Remove the upper intake manifold

• Use a 10mm socket and 3/8-inch ratchet with extensions to remove the upper intake manifold bolts.
• Lift the manifold straight up and off carefully.
• Cover the intake ports with clean rags right away to keep debris out.
• Do not let anything fall into the engine.

Step 4: Remove the ignition coils

• Unplug each ignition coil connector one at a time.
• Use a 10mm socket to remove the coil hold-down bolts.
• Pull each coil straight out of the spark plug tube.

Step 5: Remove the old spark plugs

• Use a 5/8-inch spark plug socket, extension, and universal joint adapter if needed.
• Turn each plug counterclockwise to remove it.
• Inspect the old plugs for oil, heavy carbon, or white deposits.
• Compare one old plug to the others.

Step 6: Install the new spark plugs

• Check the gap only if the plug manufacturer says it is safe to adjust.
• Thread each new plug in by hand first to prevent cross-threading.
• Use a torque wrench with the spark plug socket to tighten each plug to 18 Nm (13 ft-lbs).
• Do not use anti-seize on plugs unless the plug maker specifically allows it.

Step 7: Reinstall the ignition coils

• Add a small amount of dielectric grease inside each coil boot.
• Push each coil straight down onto its spark plug.
• Use a 10mm socket to tighten the coil bolts to 8 Nm (71 in-lbs).
• Reconnect each coil electrical connector.

Step 8: Reinstall the intake manifold and ducting

• Remove the rags from the intake ports.
• Install new intake manifold gaskets and set the manifold in place.
• Use a 10mm socket and torque wrench to tighten the intake manifold bolts to 10 Nm (89 in-lbs) in a crisscross pattern.
• Reinstall the throttle body and tighten its bolts to 10 Nm (89 in-lbs).
• Reconnect all hoses, ducts, and electrical plugs.

Step 9: Reassemble and reconnect power

• Reinstall the engine cover.
• Reconnect the negative battery cable with a 10mm wrench.
• Make sure no tools or rags are left in the engine bay.

---

✅ After Repair

• Start the engine and let it idle.
• Listen for vacuum leaks or rough running.
• Check the dashboard for a check engine light.
• If the idle is unstable, recheck every hose and connector you removed.
• Test drive the vehicle and confirm smooth acceleration.

---

💰 DIY vs Shop Cost

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

DIY Cost: $120-$260 (parts only)

You Save: $330-$640 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 3-5 hours.

---

🎯 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.