Owners of other General Motors vehicles from Chevrolet, Buick, GMC, Cadillac and Holden such as the Sonic, Spark, Malibu, Impala, Volt, Bolt, Camaro, Corvette, Trax, Equinox, Blazer, Suburban, Tahoe, Traverse, Colorado, Silverado, Express, TrailBlazer, Encore, Regal TourX, Envision, Enclave, LaCrosse, Cascada, Sierra, Canyon, Acadia, Terrain, Yukon, Savana, XT4, XT5, XT6, Escalade, CT5, CTS-V, XTS, CT6, ATS, Astra and Commodore may also find these DIY instructions to be helpful.

The OEM (original equipment manufacturer) spark plugs in this 2018 Cruze LT were part number ACDelco 41-156 iridium which are also known as GM part number 12683541 or 55490097 R6.

The owner's manual also specifies GM part number 12673527 or ACDelco 41-153 as being compatible spark plugs.

The tools needed to complete this procedure include a Torx T30 star bit screwdriver, a 10mm socket with a 1/4" drive ratchet, a 14mm spark plug socket (you could also use a 9/16" spark plug socket), an extension bar with a 3/8" drive ratchet and a tube of dielectric grease.

The first two steps are to open the hood and move to the right (driver) side of the engine.

Remove the single bolt that secures the black plastic "ECOTEC" engine cover in place by turning it in the counterclockwise direction with a Torx T-30 screwdriver.

Twist off the oil filler cap in the counterclockwise direction and set it aside in a safe place.

Gently lift the front and rear edges of the plastic cover to release the rubber friction fasteners which are attached to metal pegs or "spikes" on the top of the engine.

Set the cover aside in a safe place.

Replace the oil fill cap by twisting it on in the clockwise direction. Replacing the cap will prevent debris or other foreign objects from falling into the engine.

Set the noise insulation pad aside with the plastic engine cover for re-installation later on.

Once the two covers have been removed, you'll be able to see the four tan and black plastic ignition coils.

If you have access to compressed air or a wet/dry shop vacuum, thoroughly clean off the top of the engine to help further reduce the risk of having dust, sand or other debris fall into the spark plug wells or down into the cylinders.

Push down on the release tab and slide the electrical connector straight off the left side of the ignition coil housing.

Set the ignition coil bolt aside in a safe place.

If you have trouble removing the ignition coil due to the rubber dust boot being stuck or "frozen" to the top of the old spark plug, try gently rotating the ignition coil back and forth a few times to loosen the boot.

The spark plug wells are "slanted" or "angled" so you can't pull the ignition coils straight up out of the engine.

I normally recommend only checking or changing one spark plug at a time to help reduce the risk of having debris or foreign objects fall down into the spark plug wells.

Since the wells are slanted, you'll need to remove the second ignition coil in order to attach the spark plug socket to the top of the first spark plug.

Otherwise, the first spark plug will be obstructed by the second ignition coil housing.

Repeat the process to remove the 2nd ignition coil housing.

Slide back the red lock tab. Push in the release tab. Disconnect the power plug. Loosen the ignition coil bolt in the counterclockwise direction with the 10mm socket and a ratchet. Carefully pull the ignition coil out at an angle towards the right (driver) side of the car. Set the 2nd ignition coil aside in a safe place.

Loosen the old spark plug by carefully turning it in the counterclockwise direction.

If you have trouble loosening an old stubborn or stuck spark plug, try spraying a very small amount of penetrating oil down into the spark plug well.

Allow the penetrating oil to seep into the threads and loosen any rust or debris for at least 10 to 15 minutes.

Once the old spark plug is loose, detach the ratchet from the extension bar and spin it out the rest of the way by hand.

Carefully lift the old spark plug out of the well.

Detach the old spark plug from the socket.

If the iridium electrode tip of the old spark plug appears to be ashy white or discolored, it may have been exposed to an overheating engine.

If the old spark plug is covered in oil or soot, the engine may be burning oil and should be inspected by a professional mechanic.

If you have a spark plug gap gauge, check the new plugs to make sure the gap is correct.

The gap specification for the OEM ACDelco 41-156 spark plugs is listed as 0.051" on many parts sites.

Important Update! - The spark plug gap specification from GM has been updated to 0.028 in. or 0.7 mm.

The information below was on the Cruze Talk forum sent to a member from a GM representative. Please verify this information before modifying the gap on your spark plugs.

"The 2012 North American Cruze Service Manual spark plug gap information was incorrectly listed as 0.85 - 0.95 mm. A change is being implemented to correct that information to 0.6 - 0.7 mm. This information is in the process of being updated in dealers online service information. A service bulletin will not be issued. The spark plug gap for the Cruze 1.8L engine is the same: 0.6 - 0.7 mm.

The 2012 and 2013 North American Cruze Owner’s Manual spark plug gap will remain unchanged at 0.7 mm as they are already printed. The gap is the same for all North American model Chevrolet Cruze models with the 1.4L and 1.8L engines regardless of model year."

(Most spark plug manufacturers do not recommend using anti-seize on the threads of new spark plugs. Anti-seize lubricant can easily lead to over tightening and damage the spark plugs or the threads in the cylinder head.)

Push a new spark plug into the 14mm or 9/16" spark plug socket.

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

Carefully lower the new plug down into the well.

Try to avoid banging the electrode tip on the sides of the well or the top of the cylinder head.

Spin in the new spark plug a few turns by hand in the clockwise direction to help prevent it from becoming cross threaded.

Continue tightening the new spark plug with the 14mm or 9/16" socket and 3/8" drive ratchet to just barely past the point when you feel the new crush washer collapse.

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

Avoid over tightening the spark plugs!

If you insist on using a torque wrench, the service manual specification for the spark plugs is 18 lb-ft of torque (or about 25Nm, 24.40 Nm to be exact).

Double check that the spark plugs are tight before moving on to the next steps.

(FYI - The spark plug firing order is 1–3–4–2.)

The dielectric grease will keep out any moisture or debris and help ensure a reliable electrical connection.

Lower the ignition coil down into the spark plug well.

Push on the ignition coil to make sure the rubber dust boot is securely attached to the top of the spark plug.

Spin in the ignition coil bolt a few turns by hand in the clockwise direction to make sure it doesn't become cross threaded or fall down into the engine bay and become lost.

You should hear or feel a "click" when the power plug is securely attached.

Slide the red lock tab in towards the ignition coil to secure the connector in place.

Remove the oil fill cap by twisting it off in the counterclockwise direction.

Lower the plastic cover down over the top of the engine.

Push on the cover to secure the rubber friction fasteners to the metal pegs.

Replace the single bolt at the front right corner of the engine cover by turning it in the clockwise direction with the Torx T-30 star bit screwdriver until it is snug.

Try to avoid over tightening the Torx bolt to prevent from cracking the plastic cover.

Start the engine and listen closely for any strange noises that might indicate a problem such as a loose spark plug or a disconnected electrical connector.

If you do hear any odd noises, immediately turn off the ignition and double check the spark plugs, ignition coils and electrical connectors.

Be sure to write down the spark plug change in your vehicle's service records.

The service interval specification for the spark plugs in the owner's manual is to change them every 60,000 miles (or 96,000 kilometers).

For more, please check out all of my 2016-2019 GM Chevrolet Cruze DIY Repair & Maintenance Guides.