2019 Chevrolet Suburban Spark Plug Type & Gap

Quick reference

Why the right plug matters

Choosing the correct spark plug for your 2019 Chevrolet Suburban is crucial for optimal engine performance, fuel efficiency, and longevity. Spark plugs are not a "one size fits all" component. Key factors like heat range and electrode material significantly impact how your engine runs.

Heat Range: This refers to a spark plug's ability to dissipate heat from the combustion chamber. A plug that's too hot can lead to pre-ignition and detonation, damaging the engine. A plug that's too cold can lead to fouling, causing misfires and poor performance. The correct heat range ensures the plug tip stays at an optimal temperature to burn off carbon deposits without getting so hot that it causes pre-ignition.

Electrode Metal:

• Iridium: These are the most common and recommended for modern vehicles, including your Suburban. Iridium plugs feature a fine-wire iridium center electrode and often an iridium-enhanced ground electrode. Iridium is incredibly hard and has a very high melting point, allowing for a much smaller electrode. This smaller electrode requires less voltage to create a spark and provides a more consistent, powerful spark over a longer lifespan. They are designed for extended service intervals, typically 90,000-100,000 miles.

• Platinum: Platinum plugs are a step up from copper, featuring a platinum disc welded to the center electrode. They offer better durability and a longer lifespan than copper plugs, though not as long as iridium. Double platinum plugs have platinum on both the center and ground electrodes for even greater longevity. They are often found in vehicles that originally came with platinum plugs and typically last around 60,000 miles.

• Copper: While excellent conductors of electricity, copper plugs have a thicker center electrode and wear out much faster. They are not recommended for your Suburban as they would not meet the manufacturer's performance or longevity requirements. Their shorter lifespan means more frequent replacement, which isn't practical for coil-on-plug ignition systems.

How to gap a spark plug

While many modern iridium spark plugs come pre-gapped from the factory, it's always a good practice to verify the gap, especially since shipping and handling can sometimes alter it. A spark plug gap tool, either a wire-type or coin-style, is used for this.

To check the gap, gently insert the correct feeler gauge or wire into the space between the center and ground electrodes. It should slide in with a slight drag. If adjustment is needed, gently bend the ground electrode. For larger gaps, use the tool to slightly widen the gap. For smaller gaps, carefully tap the ground electrode on a hard, non-marring surface to close it a tiny amount. Never pry on or bend the center electrode, as this can damage the fine-wire tip of an iridium plug. Always recheck the gap after any adjustment.

Replacement procedure tips

The 2019 Chevrolet Suburban, like most modern GM vehicles, utilizes a coil-on-plug (COP) ignition system. This means each spark plug has its own ignition coil mounted directly above it.

Coil Pack Removal: To access the spark plugs, you'll need to disconnect the electrical connector from each coil pack and then remove the fasteners (usually a single bolt) holding the coil pack in place. Carefully lift the coil pack straight up to remove it from the spark plug.

Anti-Seize Debate: The use of anti-seize on spark plug threads is a topic of debate. ACDelco and General Motors generally recommend against using anti-seize on spark plug threads for their engines. Modern spark plugs often have a special coating on the threads to prevent seizing. Applying anti-seize can act as an insulator, potentially affecting the plug's ground path and altering torque readings, leading to over-tightening. If you choose to use it (against manufacturer recommendation), use a very small amount on the threads only, and reduce the torque specification by approximately 20%.

Dielectric Grease on Boots: It is highly recommended to apply a small amount of dielectric grease inside the spark plug boots (the part that connects to the top of the spark plug). Dielectric grease helps seal out moisture, prevents corrosion, and makes future removal easier by preventing the boot from sticking to the ceramic insulator of the spark plug.

Torque Specification: Always use a torque wrench to tighten spark plugs to the manufacturer's specified torque (11 lb-ft / 15 Nm for your Suburban). Over-tightening can damage the spark plug, cylinder head threads, or even crack the porcelain insulator. Under-tightening can lead to combustion gasses escaping, causing misfires or overheating the plug.

Known issues

The 5.3L and 6.2L V8 engines in the 2019 Chevrolet Suburban are known to be quite robust, and there are no widespread, specific spark plug-related "known issues" similar to the notorious Ford 3-valve engine's two-piece spark plug breakage. So, thankfully, you don't have to worry about broken shells or cracked porcelain during routine replacement if proper procedure is followed.

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