DIY: Land Rover LR3 spark plug change

Blog Feature

This is not a hard job at all. It just takes patience when loosening the spark plugs. It took us about 2 hours to do this job using all Land Rover parts from FCP Euro, including a late-night run to Wal-Mart to get another extension for the socket wrench. And yeah, we went to drive-thru, too.

Special Notes:

  1. The engine must be completely cooled down to perform this service, otherwise you increase the risk of stripping the spark plug threads in the engine’s aluminum cylinder heads. We used a box fan to cool the engine during the time it took to perform an oil change.

  2. Since the spark plugs have such a long service life (90,000 miles), they likely will be hard to remove. Be patient and turn them back and forth a lot. Do not try to muscle them out.

  3. There is plenty of room to do this job, but you will need to use two 4-inch extensions for your socket wrench. The rearward plug holes are rather close to the fenders. So you will need to separate the extension and assemble them as you insert. It’s better to use extensions that lock together. We found that a few wraps of tape sufficed to keep the extensions and socket from falling apart.

  4. We found that our standard spark plug socket was a few millimeters too wide to reach the spark plugs, which are deep in the valve covers. However, we found that a 16mm deep socket was able to do the job. It may take some trial/error/borrowing to find the perfect socket for the job.

Parts:

Tools

  • Phillips screwdriver
  • Socket wrench
  • 6mm socket
  • 8mm socket
  • T20 Torx screwdriver
  • 16mm spark plug socket
  • 2 Four-inch long socket extensions with locking ends
  • 8-inch long piece of vacuum tube
  • Torque wrench

Clearing the Way

Remove the oil cap.

Use a 6 mm socket to remove the four bolts for the engine cover.

There are plastic panels covering each row of ignition coil packs. Use a plastic pry tool to release the covers. Lift them up and slide backwards.

If the engine is not already cool, you can prop a box fan in the engine bay to cool it down.

Remove the section of air intake tube that has the resonator by undoing the two hose clamps and slipping the resonator off of the other intake tubes.

Use a T20 torx screwdriver to remove the two screws on top of the PCV valve. Move the PCV valve aside to get better access to your ignition coils. No need to disconnect the hoses.

Detach the heater hoses from the firewall.

On the driver side, remove the screw that holds the aluminum heat shield in place. Lift the heatshield out.

Removing the Spark Plugs

Remove the plug for each ignition coil by pressing the the tab at the back of the plug. You may need to do this while prying up on the front of the clip. Slide the plug off the back of the coil.

Use an 8mm socket to remove the bolt holding each ignition coil in place.

Pull each of the ignition coils out. Inspect the contacts for corrosion or dirt. Clean contacts if necessary.

Use a 16 mm socket with two 4-inch extensions to unscrew the old spark plugs. Note that the holes in the valve cover leading to the spark plugs are very narrow. If your socket does not fit through the hole smoothly, do not attempt to remove the spark plug because the socket will get stuck. Find a narrower socket.

IMPORTANT WARNING: The old spark plugs may be tight. If you apply too much force, you risk stripping out the threads in the cylinder head. A little bit of patience goes a long way in this situation: Turn the spark plug 1/16 rotation to loosen it, and then turn it in the opposite direction. Repeat this process over and over, each time bringing it a little closer to loosening up. This back-and-forth process may take a few minutes per spark plug, but eventually the old spark plug should start to turn more freely.

Put it Back Together

Use a piece of vacuum tube to reinsert the plugs into the holes. Twist the vacuum tube to get the plugs started without cross threading. Tighten them up using the tube as far as they will go.

Finish tightening the plugs with a torque wrench set at 18 foot-lbs.

Reinstall ignition coils, coil bolts, and coil plugs.

Reinstall plastic dust cover for ignition coils.

Reinstall intake resonator and PCV valve. Reattach heater hoses to the passenger side fender well.

Reinstall aluminum heat shield on driver side fender. Note the two tabs at the bottom of the heat shield that help hold it into place.

Reinstall engine cover and oil cap.

Go for a test drive.

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