2020 Chevrolet Suburban Spark Plug Type & Gap

Quick reference

Why the right plug matters

Choosing the correct spark plug for your 2020 Chevrolet Suburban is critical for optimal engine performance, fuel efficiency, and longevity. Spark plugs are more complex than they appear, with specific heat ranges, electrode materials, and designs tailored to each engine.

• Heat Range: This refers to the plug's ability to dissipate heat from the combustion chamber. A plug that's too "cold" (dissipates heat too quickly) can lead to fouling, while one that's too "hot" (retains too much heat) can cause pre-ignition and engine damage. The OEM plugs for the 2020 Suburban's 5.3L and 6.2L V8 engines are carefully chosen for the correct heat range.

• Electrode Metal: The material of the center and ground electrodes plays a significant role in a plug's lifespan and performance:

  • Iridium: This is the most common and recommended material for modern vehicles like your Suburban. Iridium is extremely hard and features a very fine electrode tip, leading to a long lifespan (often 100,000 miles or more), strong spark, and improved combustion efficiency. Both the ACDelco OEM plugs and the recommended NGK/Denso aftermarket options for your Suburban are iridium.
  • Platinum: Platinum plugs offer good durability and a longer lifespan than copper, typically lasting around 60,000-80,000 miles. They are often used as an upgrade over copper in older vehicles but are generally superseded by iridium in newer applications.
  • Copper: Copper plugs have the best conductivity but also the shortest lifespan due to the softer metal. They are typically found in older or high-performance, forced-induction applications where frequent replacement is acceptable to maintain optimal spark.

How to gap a spark plug

While many iridium spark plugs come pre-gapped, it's always a good practice to double-check and adjust if necessary. The specified gap for your 2020 Suburban's 5.3L and 6.2L V8 engines is 0.040 inches (1.0 mm).

To gap a spark plug, you'll need a gap gauge tool (wire-type or coin-style are common):

1. Measure: Carefully slide the appropriate thickness wire or the edge of the coin-style gauge between the center electrode and the ground electrode. There should be a slight drag.
2. Adjust (if needed):
   • To increase the gap: Use the bending tool on the gauge to gently pry the ground electrode away from the center electrode.
   • To decrease the gap: Gently tap the ground electrode on a hard, non-marring surface or use the bending tool to carefully push it closer.
3. Re-measure: Always re-measure after any adjustment to ensure accuracy. Avoid bending the center electrode.

Replacement procedure tips

Replacing spark plugs on your 2020 Chevrolet Suburban's L83 (5.3L) or L86 (6.2L) V8 engine is a straightforward job, but a few tips can make it smoother:

• Coil-on-Plug (COP) Removal: Your Suburban uses a coil-on-plug ignition system, meaning each spark plug has its own individual ignition coil mounted directly above it. To access the plugs, you'll need to carefully disconnect the electrical connector from each coil and then unbolt the coil (usually a 7mm or 10mm bolt). Gently twist and pull upwards to remove the coil and boot assembly.

• Anti-Seize Debate: There is ongoing debate about using anti-seize on spark plug threads. For modern spark plugs with nickel-plated shells, manufacturers like NGK and Denso generally recommend against using anti-seize. The nickel plating provides adequate anti-seize properties, and adding more can lead to over-torquing the plug due to reduced friction, potentially damaging the cylinder head threads.

• Dielectric Grease on Boots: Apply a thin layer of dielectric grease inside the spark plug boot (the part that connects to the top of the spark plug). This helps prevent moisture entry, insulates against voltage leaks, and makes future removal easier.

• One at a Time: To avoid mixing up spark plug wires or coils, it's often best to replace one spark plug at a time, from start to finish.

Known issues

Fortunately, the 2020 Chevrolet Suburban's L83 and L86 V8 engines are not widely known for specific, common spark plug breakage issues like the two-piece plugs found in some older Ford 3-valve engines. The design is generally robust.

One thing to be aware of with GM's modern V8 engines is the use of ionization-sensing technology in some coil designs. While not a "spark plug issue" per se, using the correct OEM or equivalent aftermarket spark plugs is crucial to ensure these systems function correctly and don't trigger misfire codes or illuminate the check engine light.

Always use a torque wrench to ensure spark plugs are tightened to the specified 15 lb-ft (20 Nm). Over-tightening can damage the cylinder head threads, while under-tightening can lead to combustion gas leaks or the plug backing out.

Need plugs replaced? Find a shop on Repairius.