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Chevrolet Sonic Engine Spark Plugs Replacement Guide
How to change the spark plugs in a 1st generation 2012-2014 GM Chevy Sonic with the Ecotec 1.8L I4 A18XER motor.

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2013 Sonic 1.8L I4 Engine
Pry Off Ignition Coil Cover
Coil Cover Removed
This automotive maintenance tutorial was specifically written to assist owners of the first generation (2012, 2013, 2014, 2015 & 2016) Chevy Sonic equipped with the GM "Family 1" Ecotec DCVCP 1.8 liter A18XER (2H0) inline four cylinder engine in changing the spark plugs.

Owners of other General Motors vehicles equipped with the A18XER motor, or similar Ecotec engines, such as the Chevrolet Cruze, Opel Zafira, Opel Astra, Opel Mokka and Opel Insignia may also find these DIY spark plug change instructions to be helpful.

The OEM spark plugs on this 2013 Sonic are ACDelco part number 41-122 (55585534).

A few other compatible aftermarket spark plugs include the Autolite XP3923, Denso (4504) PK20TT and the Champion 3344,

The tools needed to complete this procedure include a flathead screwdriver, a Torx T30 star bit screwdriver, a 5/8" spark plug socket with a 3/8" drive ratcheting wrench, a 6" extension bar, a spark plug gap gauge, dielectric grease and anti-seize lubricant (optional).

Ignition Coils Assembly
Remove Torx T-30 Screw
Torx Screw Removed
The first steps are to pop open the hood and then locate the rectangular plastic cover in the center of the engine.

Gently pry off the cover with a small flathead screwdriver to reveal the ignition coils assembly. Set the cover aside in a safe place.

If you have access to compressed air or a wet/dry shop vacuum, thoroughly clean off the top of the engine to help prevent debris from falling in to the spark plug wells.

Remove the two screws on the top of the ignition coil bar by turning them counter clockwise with a Torx T30 star bit screwdriver. Set the two screws aside in a safe place.

Remove 2nd Torx Screw
Orange Locking Tab
Push Out Orange Lock Tab
The electrical connector for the ignition coils assembly is located on the right side.

To disconnect it, first slide the orange locking tab to the right with a small flathead screwdriver.

Then press the release button on the plug and slide it straight off to the right.

Press Release - Unplug Coils
Pull Out Ignition Coils Bar
4 Ignition Coils Removed
Carefully lift the ignition coils assembly straight up and out of the engine.

If you have trouble removing it, try gently wiggling the bar while continuing to pull up.

Set the ignition coils assembly aside in a safe place.

Spark Plug Well
Loosen Old Spark Plug
Spin Out Old Plug By Hand
Attach the 5/8" spark plug socket to a 6 inch extension bar and the 3/8" drive ratcheting wrench.

Lower the spark plug socket down over the first spark plug.

Carefully loosen the old spark plug by turning it counter clockwise. Once the spark plug is loose, detach the ratcheting wrench and spin it out by hand with the extension bar.

If the old spark plug won't spin, do not use excessive force to avoid cracking the ceramic portion of the plug.

Spray a small amount of penetrating oil such as PB Blaster, Liquid Wrench or Kano Kroil and wait at least 15 minutes or more before attempting to loosen it again. If you don't have any penetrating oil, try spraying some WD-40 or warm up the engine for a few minutes to help expand the metal engine block.


Lift Out Old Spark Plug
ACDelco Iridium 41-122
Empty Spark Plug Well
Lift the old spark plug out of the well and pull it out of the socket. If the rubber insert inside the spark plug socket comes out with the plug, push it back in to the socket.

To further reduce the chance of having something drop down in to the spark plug well and in to the cylinder head, I'd recommend only checking or replacing one spark plug at a time.

The OEM iridium tipped spark plugs on this 2013 Sonic are ACDelco 41-122 (they were also marked with the # 55585534).

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

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

If you have a spark plug gap gauge, verify that the electrode gap on the new spark plugs is .025". If the gap is incorrect, it may have been damaged during shipping and the plug should be exchanged for a new one.

Apply Dielectric Grease
Spin New Spark Plug
Tighten New Plug Clockwise
Apply a small amount of dielectric grease to the openings in the rubber dust boots at the bottom of the ignition coils.

The dielectric grease will help the ignition coil form a better electrical contact with the spark plug and keep out any moisture.

Insert the new spark plug in to the spark plug socket attached to the 6" extension bar. The socket should have a rubber insert or a magnet to securely hold the new plug in place.

An optional step is to apply a tiny amount of anti-seize lubricant to the upper metal threads of the new spark plug. This will make the plugs easier to take out if they are not changed again for another 100k miles. Do not get any of the anti-seize on the electrode tip at the bottom of the new spark plug. Some spark plug manufacturers recommend against using anti-seize since it can lead to over tightening.

If you do apply anti-seize to the threads of the new spark plug, less force will be necessary to tighten them.

Carefully lower the new spark plug down in to the well and try to avoid hitting the electrode tip on the top of the cylinder head.

Spin in the new plug by hand in the clockwise direction until it stops.

Attach the ratcheting wrench to the extension bar and tighten the new spark plug to just barely past the point when you feel the metal crush washer collapse. Do not over tighten the spark plugs to prevent from cracking the ceramic body or stripping the aluminum threads.

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

Re-Insert Ignition Coils
Push On Power Plug
Tighten Torx T30 Screws
Carefully lower the ignition coils assembly down over the new spark plugs with the electrical connector situated on the right side of the engine.

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

Slide the orange locking tab in to the left to lock the connector.

Tighten 2nd Coil Pack Screw
Replace Coils Cover
Spark Plugs Replaced
Re-insert the two screws and tighten them in the clockwise direction with the Torx T30 screwdriver until they are snug.

Start the engine and listen closely for any sounds that may indicate a problem.

For more, check out my other Chevy Sonic Repair & Maintenance Guides.

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