Owners of other Toyota or Scion vehicles equipped with the 2.5 liter 2AR-FE engine such as the Camry and tC or other models with similar motors such as the Yaris, Corolla, Prius, Sienna, Avalon, Venza, and Matrix, Tacoma, Highlander, and 4Runner, may also find these DIY instructions to be helpful.

The tools and other items needed to complete this procedure include a 10mm socket with a 1/4" drive ratcheting wrench, a 5/8" spark plug socket with a 6" extension bar, a 3/8" drive ratchet, dielectric grease, anti-seize lubricant and a spark plug gap gauge.

The OEM iridium long life spark plug is Denso part # SK16HR11 (3417).

Other compatible spark plugs include the following with their art numbers: Bosch (9609) FR8MII33X, Denso (5343) IKH16, Champion REC12WMPB5 (9055), NGK LFR5AIX-11 (4469) or 5018, Bosch 9909 or 4516, and the Pulstar dg1i.

Pop open the hood and pull off the black plastic engine cover.

If you have access to compressed air or a wet/dry shop vacuum, clean off the top of the engine to reduce the chance of having debris fall in to the spark plug well.

Press the release tab on the ignition coil's power connector and pull it straight off.

Set the 10mm bolt aside in a safe place.

I'd recommend checking or replacing one spark plug at a time to help prevent from dropping something in to the cylinder head.

Gently rotate the ignition coil back and forth a few times to make sure that the rubber boot is not stuck to the spark plug.

Lift the ignition coil out of the spark plug well and set it aside in a safe place.

Carefully lower the spark plug socket down over the tip of the spark plug.

Loosen the spark plug by gently turning it counter clockwise.

(The spark plug socket should have a rubber insert or magnet to securely hold the plug when it is removed.)

If the spark plug won't turn, spray in some penetrating oil such as PB Blaster, Liquid Wrench or Kano Kroil and wait 15-30 minutes or more before trying again. If you don't have any penetrating oil, try spraying some WD-40 or just warm up the engine for a few minutes to expand the metal engine block.

Lift the old spark plug straight out of the well and inspect it.

If the end of the old spark plug looks ashy white, they may have been exposed to high temperatures such as engine overheating or they are the incorrect heat range for your driving conditions and/or environment.

If the old spark plugs are dark grey or covered in black soot, the engine may be burning oil and should be checked out by a professional.

I recommend buying the Bosch (9609) FR8MII33X iridium spark plugs since they have excellent reviews on Amazon.

It is still a good idea to check that the gap is correct using a spark plug gap gauge disc. If the gap is not very close to 0.044", exchange the plug for a new one.

Pull the old spark plug out of the 5/8" socket and push in the new one until the rubber insert or magnet securely holds it in place.

An optional step is to apply a tiny amount of anti-seize lubricant to the upper threads of the new spark plug. This will make the plugs easier to remove if they are not replaced again for another 100,000 miles. Do not get any anti-seize on the electrode at the bottom of the new spark plug. Most spark plug manufacturers recommend that you should not use anti-seize since it lead to over tightening.

Carefully lower the new spark plug attached to the socket and extension bar down in to the well.

Try to avoid hitting the electrode at the bottom of the plug against the engine block.

Then attach the ratchet and carefully continue tightening the new plug until just past the point when you feel the crush washer at the top of the threads collapse.

If you have a very sensitive and reliable torque wrench, the service manual specification for the spark plugs is 18 lb-ft (or 25 Nm).

If you applied anti-seize lubricant to the threads, less force will be necessary to tighten the plugs. I've read that NGK recommends using 30% less torque when using anti-seize which would be 12.6 lb-ft (or just set your torque wrench to 13 lb-ft).

Do not over tighten the plugs to avoid cracking the ceramic part of the plug or stripping the aluminum threads in the cylinder head.

Apply a small amount of dielectric grease to the opening of the rubber dust boot at the bottom of the ignition coil.

This will help prevent it from becoming stuck to the tip of the new spark plug and keep out moisture.

Lower the ignition coil down over the tip of the new spark plug and twist it a few times to distribute the dielectric grease.

Tighten it with the 10mm socket and ratcheting wrench to just past hand tight.

The service manual specification for tightening the ignition coil bolts is 7 lb-ft (or 10 Nm).

Try to avoid over tightening the bolt to prevent from cracking the plastic ignition coil housing.

Slide the power connector straight on to the ignition coil until it snaps in place.

Start the engine and listen for any strange sounds.

If all goes well, replace the engine cover and close the hood to complete the job.

According to the maintenance schedule in the owner's manual the service interval for the iridium spark plugs is 120,000 miles or 144 months.

For more, check out my other Toyota RAV4 Repair & Maintenance Guides.