How to Change Sparkplugs in Vehicles

by Contributing WriterUpdated June 12, 2017

Spark plugs on today's cars last a lot longer than they used to, thanks to advanced ignition technologies, cleaner running engines and tighter internal clearances on the engine. They do still wear out, however, and eventually you will need to replace them with new units. Fortunately, this isn't very difficult to do and can be done Vehicles home in the driveway with some basic tools.

Under The Hood:

 How to Change Sparkplugs in a 2003 Toyota Corolla

Pop the hood of the Corolla and locate the spark plug wires. These are the four ignition wires that run from the side of the engine across the top and end at the top. Hold the base of the spark plug wire on the far left side of the cylinder head and pull it up while twisting it to remove the wire from the plug.

Install the spark plug socket onto the end of the 3/8-inch extension, then install that onto the ratchet. Unscrew the spark plug from the engine and discard it.

Gap the replacement spark plug to .044 on the spark plug gapping tool. Then install it into the head in the reverse order the previous plug was removed. Push the spark plug wire onto the plug until it clicks into place.

Move to the next spark plug wire to the right, then repeat Steps 1 to 4 until all of the spark plugs are replaced in the Corolla.

Items you will need

  • 3/8-inch ratchet and extension

  • Spark plug socket

  • Spark plug gapping tool

  • Spark plugs

 How to Change Sparkplugs in a 2.4L Engine

Allow the engine to cool off for at least 30 minutes before beginning. Unhook the negative battery cable a few minutes before you start.

Disconnect one sparkplug wire at a time to avoid cross-connecting the wires when you replace the spark plug. If you don't have the sparkplug wire removal tool, you will have to wiggle the wire to disconnect its boot from the sparkplug.

Use the sparkplug socket attachment to remove the sparkplug from the cylinder. This is a good time to inspect the well for contaminants. If you see oil or water in the sparkplug well, you may have an engine problem that caused premature sparkplug failure.

Insert the new sparkplug and carefully tighten with your hand to avoid cross-threading the cylinder thread. After the sparkplug is secure, tighten it with the sparkplug socket.

Reattach the sparkplug wire and repeat the procedure for all four sparkplugs.

Items you will need

  • Pliers

  • Socket wrench set

  • Sparkplug wire removal tool

  • Sparkplug socket attachment

  • Replacement sparkplugs

 How to Change the Sparkplugs on an FJ Cruiser

Removing Spark Plugs

Pop the hood using the release lever located inside the vehicle, near the driver's side footwell.

Make sure the engine is cold. Disconnect the battery and check the temperature of the engine.

Remove the plastic, engine-bay cover; the air-intake pipe on the passenger side; and two black brackets on the driver's side, located directly behind the engine oil filler cap. Of the two brackets, one will be nearest the firewall. Locate the end of the vent-tube that's behind and slightly to the left of that bracket, and disconnect it.

Unplug the black electrical plugs from every coil pack.

Unbolt the coil packs and remove them by pulling them up.

Uninstall the spark plugs using the spark plug socket, extension and wrench.

Installing Spark Plugs

Hand-tighten the new spark plugs into position and then tighten the spark plugs to 14 foot-lbs. with the torque wrench.

Reinstall all coil packs onto the new spark plugs and reattach them to their corresponding electrical plugs.

Reinstall the two driver side brackets, vent-tube and the passenger side air-intake pipe. Reattach the plastic engine bay cover and reconnect the battery.

Items you will need

  • Socket set including sockets, spark plug socket, wrench and extension.

  • Torque wrench

  • Screwdriver(s)

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