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Buick LaCrosse Spark Plugs Replacement Guide
How to change the engine spark plugs in a 2nd generation 2010 to 2016 Buick LaCrosse sedan with the 3.6L V6 motor.

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2016 LaCrosse 3.6L V6
Twist Off Oil Filler Cap
Remove Counterclockwise
This automotive maintenance tutorial was specifically written to assist owners of the second generation (2010, 2011, 2012, 2013, 2014, 2015 & 2016) GM Buick LaCrosse sedan in checking or changing the engine spark plugs in the LFX or LLT 3.6 liter V6 motors.

Owners of other General Motors vehicles such as the Chevrolet Impala, Monte Carlo, Malibu, Spark, Sonic, Cruze, Volt, SS, Camaro, Caprice, Corvette, Trax, Equinox, Traverse, Tahoe, Suburban, Colorado, Silverado, Buick Verano, Regal, Cascada, Encore, Enclave, Envision, GMC Canyon, Sierra, Terrain, Acadia, Yukon, Savana, Cadillac CT6, ATS-V, ATS, ELR, CTS, XTS, XT5, SRX, Escalade and Holden Commodore may also find these DIY instructions to be helpful.

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


The OEM spark plugs are the ACDelco 41-109 or GM part number 12622561.

A few compatible replacement spark plugs with their part numbers include the following: Autolite XP5263, NGK LTR6IX-11, Denso (4719) ITV20TT, Champion RE10PMC5 (3032) and Bosch (6728) HR7MPP30X.

Pull Off Plastic Engine Cover
Rubber Friction Fasteners
Metal Pegs On Top
The first few steps are to open the hood, twist off the oil filler cap in the counterclockwise direction and gently pull off the plastic engine cover.

Set the plastic engine cover aside in a safe place.

Either replace the oil filler cap or insert a clean rag in to the hole to prevent from having debris fall in to the engine.

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

To access and change the three spark plugs on the rear of the engine, you'll need an assortment of extension bars and also a universal swivel joint. It can be challenging to replace the rear three spark plugs, but having the right tools makes it a lot easier.

Pull Off Plastic Tube
Ignition Coil
Grey Plastic Lock Tab
For easier access to the front three spark plugs, disconnect the plastic tube that runs across the top of the engine.

Gently slide out the grey plastic locking on the ignition coil's electrical connector.

Slide Out Locking Tab
Press Tab - Pull Off Plug
Loosen 10mm Bolt
Push in the black plastic tab to release the power plug before sliding it straight off the base of the ignition coil.

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

10mm Bolt Removed
Pull Out Ignition Coil
Spark Plug Well
Spin out the 10mm bolt and set it aside in a safe place.

Rotate the ignition coil back and forth a few times to make sure that the rubber boot at the bottom of the ignition coil 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.

I recommend only checking or changing one spark plug at a time to further reduce the change of having something fall down in to the engine.

5/8" Spark Plug Socket
Loosen Counterclockwise
Spin Out By Hand
Attach the 5/8" spark plug socket to an extension bar and the 3/8" drive ratcheting wrench.

Lower the socket down in to the well and attach it to the top of the old spark plug.

Loosen the old spark plug by turning it counterclockwise.

Try to avoid using excessive force to loosen the old spark plug, which may cause it to crack or break off entirely.


Lift Out Old Spark Plug
Inspect Old Spark Plug
Lower In New 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.

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 and detach it from the socket.

Carefully inspect the old spark plugs.

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

The OEM (original equipment manufacturer) spark plugs in this 2016 LaCrosse are the ACDelco # 41-109 iridium.

I recommend buying either the OEM plugs or the Autolite XP5263 spark plugs which have excellent reviews on Amazon.

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.

An optional step is to apply some anti-seize grease to the threads on the new spark. Most spark plug manufacturers recommend that you should not use anti-seize since it can lead to over tightening. But it your old spark plugs were very difficult to remove at 100,000 miles, you may want to consider using some. Just remember to use less torque when you tighten the plugs.

Spin In Clockwise By Hand
Tighten With Wrench
Apply Dielectric Grease

Push the new spark plug in to the socket.

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

Lower the new spark plug down in to the well.

Spin in the new spark plug by hand in the clockwise direction until it makes contact with the engine block.

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

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

(Remember, if you used anti-seize lubricant, you'll have to be extra careful to avoid over tightening the new plug.)

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

The dielectric grease will help keep out any moisture or dust.

Lower In Ignition Coil
Spin In 10mm Bolt
Tighten 10mm Clockwise
Lower the ignition coil in to the spark plug well and rotate it back and forth a few times to help spread the dielectric grease.

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

Tighten the bolt with the 10mm socket and a 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 Power Plug
Slide In Lock Tab
Re-Attach Plastic Hose
Push the power plug straight on to the base of the ignition coil until it clicks securely in to place.

Slide the grey plastic locking tab in to secure the connector.

Re-attach the plastic vacuum tube to the engine.

Push On Engine Cover
Spin On Oil Filler Cap
Spark Plugs Replaced
Lower the plastic engine cover in to place and push on it to secure the rubber friction fasteners to the metal pegs.

Tighten the oil filler cap in the clockwise direction.

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

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

For more, check out my other 2010-2016 Buick LaCrosse DIY Repair & Maintenance Guides.

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