2020 Chevrolet Silverado 2500HD Spark Plug Guide

Quick Reference: 2020 Silverado 2500HD Spark Plugs

Why the Right Spark Plug Matters

The spark plugs in your Silverado's engine are small but mighty, responsible for igniting the air-fuel mixture that powers your truck. Using the correct plug is critical for performance, fuel economy, and engine longevity.

• Heat Range: This refers to the plug's ability to dissipate heat. A plug that's too "hot" can lead to pre-ignition, while a "cold" plug can foul with carbon deposits. The original equipment (OE) plug is designed for the specific operating temperatures of your engine.
• Electrode Material:
  • Iridium: The 2020 Silverado 2500HD with the 6.6L V8 comes with iridium-tipped spark plugs from the factory. Iridium is an extremely hard and durable precious metal, allowing for a very fine center electrode. This sharp point requires less voltage to create a spark, resulting in a more consistent and efficient combustion event. Iridium plugs offer the longest service life, often exceeding 100,000 miles.
  • Platinum: A good alternative to iridium, platinum plugs also offer long life and excellent performance, though they may not last quite as long as iridium.
  • Copper: While once the standard, copper plugs have the shortest lifespan. They are still used in some applications but are not recommended for the 2020 Silverado 2500HD.

How to Gap a Spark Plug

Properly gapping your spark plugs is a crucial step. The gap is the distance between the center and ground electrodes. Even a small variance can affect engine performance.

1. Use a Feeler Gauge or Wire-Type Gauge: These tools have blades or wires of precise thicknesses. Do not use the ramp-style gauges often found at parts store counters, as they can damage the delicate iridium tip.
2. Check the Gap: Slide the correct thickness wire or blade between the electrodes. It should have a slight drag. If it's too loose or too tight, the gap needs to be adjusted.
3. Adjusting the Gap: To adjust, gently bend the ground electrode (the curved part) toward or away from the center electrode. Use the tool on the gapping gauge for this; never pry against the center electrode.

Replacement Procedure Tips

The 6.6L V8 in the 2020 Silverado 2500HD uses a modern coil-on-plug ignition system, which means each spark plug has its own ignition coil mounted directly on top of it. This makes the replacement process relatively straightforward.

• Coil-on-Plug Removal: After disconnecting the negative battery terminal, unplug the electrical connector to the ignition coil. Then, remove the single bolt holding the coil in place. The coil can then be gently twisted and pulled straight up to remove it.
• The Anti-Seize Debate: There is much debate on whether to use anti-seize compound on spark plug threads. The short answer: follow the plug manufacturer's recommendation. Many modern plugs, including the ACDelco and NGK plugs for this truck, have a special plating on the threads that provides the same anti-seize properties. Adding more can lead to over-torquing.
• Dielectric Grease: It is highly recommended to apply a small amount of dielectric grease to the inside of the spark plug boot (the part of the coil that connects to the plug). This prevents the boot from sticking to the plug, makes future removal easier, and helps seal out moisture.

Known Issues

While some engines are notorious for spark plug-related issues (like the Ford 3-valve engines and their two-piece plugs that can break off in the head), the GM 6.6L V8 (L8T) in the 2020 Silverado 2500HD is not known for any widespread spark plug problems. The design is robust and the replacement procedure is straightforward for a modern V8.

Need plugs replaced? Find a shop on Repairius.