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Toyota Yaris Engine Spark Plugs Replacement Guide
How to change the engine spark plugs in a 3rd generation 2012 to 2016 Toyota Yaris with the 1NZ-FE 1.5L I4 motor.

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2015 Yaris 1.5L I4 Engine
Plastic Engine Cover
Loosen Four Nuts
This automotive maintenance tutorial was specifically written to assist owners of the third generation (2012, 2013, 2014, 2015 & 2016) Toyota Yaris in checking or changing the engine spark plugs in the 1NZ-FE 1.5 liter VVT-i inline four cylinder motor.

Owners of other Toyota, Lexus or Scion vehicles such as the 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 are Denso SK16R11 or NGK IFR5T11.

A few other compatible replacement spark plus with their part numbers include the following: NGK 7090 BKR5EGP, Denso (4503) PK16TT, Bosch (6702) FR8DPP30X, Autolite AP3924, Pulstar (be1h10), Champion RC12WMPB4 (9202) and Toyota 90080-91184.

The tools and other items needed to complete this procedure include a 10mm socket with a 1/4" drive ratchet, a 5/8" spark plug socket, a 6" extension bar, a 3/8" drive ratchet and a tube of dielectric grease.

Two Nuts - Front Edge
Loosen Counterclockwise
Four 10mm Nuts Removed
The first two steps are to open the hood and then locate the four nuts on the plastic engine cover.

There are two nuts on the top of the engine cover and two on the front edge.

Remove the four nuts by turning them counterclockwise with a 10mm socket and a 1/4" drive ratchet.

Set the four nuts aside in a safe place.

Lift Front of Engine Cover
Engine Cover Removed
Four Ignition Coils
Lift the front of the engine cover and then pull it off.

Set the plastic engine cover aside in a safe place.

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

Electrical Connector
Press Release Tab - Pull Off
Loosen 10mm Bolt
I recommend only checking or changing one spark plug at a time to further reduce the chance of having something fall down in to the cylinders.

Push in the release tab on the electrical connector before sliding it off the end of the ignition coil.

Remove the single bolt that holds the ignition coil housing in place by turning it counterclockwise with a 10mm socket and a 1/4" drive ratchet.

10mm Bolt Removed
Rotate Back & Forth
Lift Out Ignition Coil
Set the 10mm bolt aside in a safe place.

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

Pull 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 6" extension bar and a 3/8" drive ratchet.

I like to wrap some painter's tape around the socket to hold it in place to the extension bar to keep the socket from getting stuck down in the spark plug well.

Lower the socket down on to the old spark plug.

Gently loosen the old spark plug by rotating it counterclockwise.

Try to avoid using excessive force to loosen the old spark plug to prevent from cracking the ceramic part of the plug.

If you have trouble loosening the old spark plug, spray in a small amount of penetrating oil such as PB Blaster, Liquid Wrench or Kano Kroil and wait at least 15 to 30 minutes before trying to loosen it again. If you don't have any penetrating oil, try spraying some WD-40 or warm up the engine for about 10 to 15 minutes to help expand the metal engine block.

Spin Out By Hand
Lift Out Old Spark Plug
Inspect Old Spark Plug

Once the old 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 and detach it from the socket.

Inspect both sides of the old spark plug.

If the electrode end of the old spark plug looks ashy white, the plugs might have been exposed to high temperatures such as overheating or they might be the incorrect heat range for your driving conditions or local climate.

On the other hand, if the old spark plug is dark grey or covered in black soot, the engine may be burning oil and should be examined by a professional mechanic.


Lower In New Spark Plug
Spin In By Hand
Tighten Clockwise
An optional step is to apply some anti-seize lubricant grease to the threads on the new spark plug. Most spark plug manufacturers recommend that you should not use anti-seize since it can lead to over tightening.

I recommend buying the OEM iridium tipped spark plugs which are the Denso SK16R11 or the NGK IFR5T11.

If you have a spark plug gap gauge, check the gap on the new spark plugs. They should be pre-gapped from the factory to the correct specification. The owner's manual specifies a gap of 0.043 in. (1.1mm) while Denso and NGK specify .044".

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

Carefully lower the spark plug down in to the well and spin it in by hand in the clockwise direction until it makes contact with the cylinder head. Spinning it in by hand will help prevent the new spark plug from becoming cross threaded.

Attach the 3/8" drive ratcheting wrench to the 6" extension bar and continue tightening the new spark plug in the clockwise direction.

If you are re-installing the old spark plug, only tighten it to a tiny fraction of a turn past hand tight.

If you are installing a brand new spark plug, tighten it to just past the point when you feel the new crush washer collapse.

Do not over tighten the spark plug to prevent from cracking the ceramic body or stripping the aluminum threads.

If you used anti-seize grease lubricant, be very careful to not over tighten the spark plug.

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

Apply Dielectric Grease
Lower In Ignition Coil
Rotate Back & Forth
Apply a small amount of dielectric grease to the opening in the rubber boot at the bottom of the ignition coil housing.

The dielectric grease will help keep out debris or moisture to maintain a reliable electrical connection.

Lower the ignition coil in to the spark plug well and rotate it back and forth a few times to help distribute the dielectric grease.

Re-Insert 10mm Bolt
Tighten 10mm Clockwise
Push On Power Plug
Line up the hole in the ignition coil with its corresponding hole on the top of the engine.

Re-insert the 10mm ignition coil bolt and spin it in a few turns in the clockwise direction by hand to prevent it from becoming cross threaded.

Tighten the bolt with a 10mm socket and a 1/4" drive ratchet to just past hand tight. Try to avoid over tightening the bolt to prevent from cracking the plastic ignition coil housing.

Push the power plug straight on to the ignition coil until it clicks securely in to place.

Spark Plugs Replaced
Replace Plastic Cover
Spin On 10mm Nuts
Lower the plastic engine cover down in to place.

Spin on the four nuts in the clockwise direction a few turns by hand to prevent them from becoming cross threaded.

Tighten Clockwise
Two Front Edge Nuts
4th Nut Replaced
Tighten the four 10mm nuts in the clockwise direction until they are snug.

Try to avoid over tightening the nuts to prevent from cracking the plastic engine cover.

Start the engine and listen for any strange sounds that might indicate a problem such as a faulty ignition coil, a disconnected power plug or a loose spark plug.

Be sure to record the spark plug change in your car's service records.

For more, check out all of my 2012-2016 Toyota Yaris DIY Repair & Maintenance Guides.

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