2018 Chevrolet Malibu Spark Plug Type & Gap

Quick Reference

Why the right plug matters

Choosing the correct spark plug for your 2018 Chevrolet Malibu is crucial for optimal engine performance, fuel efficiency, and emissions. There are several factors to consider, including heat range, electrode material, and gap.

Heat Range: Spark plugs are designed with a specific heat range, which refers to their ability to dissipate heat from the combustion chamber. A "cold" plug dissipates heat quickly and is suitable for high-performance engines, while a "hot" plug retains more heat and is better for common use. Using a plug with an incorrect heat range can lead to pre-ignition or fouling, both of which can damage your engine.

Electrode Metal: The material of the electrode significantly impacts the plug's lifespan and performance.

• Iridium: These plugs offer the longest lifespan and best performance due to iridium's extreme durability and high melting point. They are standard in most modern vehicles, including your Malibu.
• Platinum: Platinum plugs provide a good balance of performance and longevity, often lasting longer than copper plugs. They are a good alternative if iridium isn't available.
• Copper: While copper plugs offer excellent conductivity, they have the shortest lifespan and are not typically recommended for modern engines like those in the Malibu, which are designed for long-life iridium plugs.

How to gap a spark plug

The spark plug gap is the distance between the center and ground electrodes. An incorrect gap can lead to misfires, reduced fuel economy, and potential damage to the ignition system. Always check the gap on new plugs, even if they are pre-gapped, as shipping can sometimes alter it.

To gap a spark plug, you'll need a wire-type spark plug gapping tool. Gently slide the appropriate gauge wire between the electrodes. If the gap is too small, use the tool's ramp or a gentle lever action to widen it slightly. If it's too wide, carefully tap the ground electrode on a solid, non-abrasive surface to close the gap. Avoid bending the center electrode, as this can damage the plug.

Replacement procedure tips

Replacing spark plugs on your 2018 Chevrolet Malibu is a manageable DIY task for most enthusiasts, but careful attention to detail is essential.

1. Coil-on-Plug Removal: Both the 1.5L and 2.0L engines use a coil-on-plug (COP) ignition system. This means each spark plug has its own ignition coil directly mounted on top. To access the spark plugs, you'll need to disconnect the electrical connector from each coil and then gently pull the coil straight up to remove it. Avoid yanking or twisting, as this can damage the coil or the boot.
2. Anti-Seize Debate: There is ongoing debate about using anti-seize compound on spark plug threads. Most modern spark plugs have a special coating on the threads that prevents seizing, and applying anti-seize can actually lead to over-torquing. Chevrolet/GM generally recommends against using anti-seize on coated spark plugs. Always consult your vehicle's service manual or the spark plug manufacturer's recommendations.
3. Dielectric Grease on Boots: Apply a small amount of dielectric grease inside the spark plug boot (the rubber part that connects the coil to the plug). This helps seal out moisture, prevents corrosion, and makes future removal easier.
4. Torque is Key: Always use a torque wrench to tighten spark plugs to the manufacturer's specified torque value (18 lb-ft or 25 Nm for both engines). Overtightening can strip the threads in the cylinder head or crack the spark plug's porcelain insulator. Undertightening can allow combustion gases to escape, leading to reduced performance and potential damage.

Known Issues

Fortunately, there are no widespread "known issues" specifically related to spark plug breakage or unique failure modes for the 2018 Chevrolet Malibu's 1.5L LFV or 2.0L LTG engines, unlike some other manufacturers (e.g., Ford's problematic 3-valve engine spark plugs). However, proper maintenance and using the correct spark plugs are crucial to prevent any general issues like misfires or reduced engine performance.

Need plugs replaced? Find a shop on Repairius.