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Toyota 4Runner Spark Plugs Replacement Guide
How to change the spark plugs in a 5th generation 2010 to 2016 Toyota 4Runner with the 1GR-FE 4.0L V6 motor.

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Paul B. Michaels
Author & Photographer
Auto Mechanic Since 1989

2015 4Runner 4.0L V6 Engine
Lift Front of Engine Cover
Pull "C" Sockets Off Bar
This automotive maintenance tutorial was specifically written to assist owners of the fifth generation (2010, 2011, 2012, 2013, 2014, 2015 & 2016) Toyota 4Runner SUV in checking or changing the engine spark plugs in the 1GR-FE 4.0 liter V6 motor.

Owners of other Toyota, Lexus or Scion vehicles such as the Yaris, Corolla, Matrix, Prius, Camry, RAV4, Sienna, Tacoma, Tundra, FJ Cruiser, Venza, Highlander, Avalon, Sequoia, Land Cruiser, IS 250, ES 350, GS 350, tC, xB, xD, iQ and FR-S may also find these DIY instructions to be helpful.

The OEM spark plugs in this 2015 Toyota 4Runner are the Denso SK16HR11 iridium.

A few other compatible spark plugs with their part numbers are as follows: NGK (4469) LFR5AIX-11, Toyota 90919-01233, Champion REC12WMPB5 (9055), Denso (4703) IKH16TT, Autolite APP5325 and Pulstar DG1H10.

The items needed to complete this procedure include a 10mm socket, a 1/4" drive ratcheting wrench, a 5/8" spark plug socket, an extension bar, a 3/8" drive ratcheting wrench and a tube of dielectric grease.

Right Side of Engine
Ignition Coil
Under Rubber Hoses
The first step is to open the hood.

If the SUV has been driven recently, allow the engine to cool off for an hour or two.

Gently lift the front edge of the plastic engine cover and then pull it forward to disengage the "C" shaped sockets from the mounting bar.

A few of the six spark plugs can be easily accessed with out much extra work.

You may need to remove a metal bar, a bracket or a rubber hose or two to reach the other spark plugs. Most of the bracket bolts are 12mm.

Left Side of Engine
Loosen 10mm Bolt
10mm Bolt Removed
Loosen the single silver metal bolt that secures the black plastic ignition coil housing to the top of the engine by turning it counterclockwise with a 10mm socket and a 1/4" drive ratcheting wrench.

Set the 10mm bolt aside in a safe place.

Disconnect Power Plug
Rotate Ignition Coil
Lift Out Ignition Coil
Press the tab on the electrical connector before sliding the power plug straight off the ignition coil.

Rotate the ignition coil back and forth a few times to make sure that the rubber boot at the bottom is not stuck or "frozen" to the top of the old spark plug.

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

Spark Plug Well
5/8" Spark Plug Socket
Loosen Counterclockwise
Attach the 5/8" spark plug socket to the extension bar and the 3/8" drive ratcheting wrench.

I secured the socket to the extension bar with some blue painter's tape to avoid having the socket get stuck down in the spark plug well.

Lower the socket over the old spark plug and loosen it in the counterclockwise direction.

Try to avoid using excessive force to prevent from cracking the old spark plug.

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.


Spin Out Old Spark Plug
Lift Spark Plug Out of Well
Denso # SK16HR11
Once the spark plug is loose, detach the ratcheting wrench from the extension bar and spin it out the rest of the way by hand.

Lift the old spark plug out of the well.

Pull the old spark plug out of the socket and inspect it.

The OEM spark plugs in this 2015 Toyota 4Runner were the Denso SK16HR11 iridium, which should be good for another 100,000 miles.

On some 1GR-FE engines, you may discover that the OEM spark plugs on the passenger side are different from the driver side.

If the electrode end of the old spark plug looks ashy white, the plugs might have been exposed to high temperatures such as engine overheating or they could be 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 could be burning oil and should be checked by a professional mechanic.

If you have a spark plug gap gauge, check the gap on the new spark plugs.

They should already be pre-gapped to the correct setting from the factory.

Spin In New Spark Plug
Tighten Clockwise
Apply Dielectric Grease
Push the new spark plug in to the socket and carefully lower it down in to the well.

The spark plug socket should have a rubber insert or a strong magnet to hold the new plug securely in place.

Spin the new spark plug in by hand a few turns until it makes contact with the cylinder head. Tightening it by hand at first will help prevent it from becoming cross threaded.

Attach the 3/8" drive ratcheting wrench to the extension bar and tighten the new spark plug in the clockwise direction to just barely past the point when you feel the new crush washer collapse.

If you are re-installing the old spark plugs, only tighten them to just a small fraction of a turn past hand tight.

Try to avoid using excessive force to prevent from cracking the new plug or stripping the aluminum threads.

Double check that the new spark plug is tight before moving on to the next step.

Apply some dielectric grease to the opening in the rubber dust boot at the bottom of the ignition coil.

The dielectric grease will help prevent corrosion and also keep out any moisture or debris.

Lower In Ignition Coil
Replace 10mm Bolt
Tighten 10mm Clockwise
Lower the ignition coil down in to the spark plug well.

Spin in the 10mm bolt a few turns by hand in the clockwise direction to prevent it from becoming cross threaded.

Tighten the bolt in the clockwise direction with the 10mm socket and 1/4" drive ratcheting wrench until it is snug.

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

Push On Electrical Connector
Metal Brackets
Remove To Access Plugs
Push the power plug straight on to the ignition coil until it clicks securely in to place.

Be careful when you remove any rubber hoses. Squeeze them first to check if they contain coolant.

It would be useful to have some wobble extensions and universal swivel joints to help reach the other spark plugs.

Metal Bars & Rubber Hoses
Line Up "C" Sockets & Bar
Push On Plastic Engine Cover
Line up the two "C" shaped sockets on the rear edge of the plastic engine cover and push them on to the mounting bar.

Push the front edge of the plastic engine cover down in to place.

Start the engine and listen for any strange sounds that might indicate a loose spark plug or a disconnected power plug.

For more, check out my other 2010-2016 Toyota 4Runner DIY Repair & Maintenance Guides.

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