2017 GMC Yukon Spark Plug Type, Gap & Torque Specs

When it’s time to tune up your 2017 GMC Yukon, getting the spark plugs right is crucial to keeping that heavy-duty V8 running smoothly and efficiently. The 2017 Yukon is equipped with GM's EcoTec3 engines—either the 5.3L V8 (L83) or the 6.2L V8 (L86). Both engines utilize advanced direct injection and require high-quality iridium spark plugs to maintain factory performance, fuel economy, and proper coil operation.

Below is the definitive guide to your Yukon’s spark plug specifications, replacement intervals, and installation tips, straight from an ASE-certified master technician.

Quick reference

Why the right plug matters

Choosing the correct spark plug isn’t just about making the engine run; it’s about heat range and electrode metallurgy. The 2017 GMC Yukon’s EcoTec3 V8 engines run high compression ratios and rely on coil-on-plug ignition systems.

Factory plugs are iridium. Iridium is much harder and more durable than platinum or standard copper. If you downgrade to a copper or single-platinum plug, the intense heat and cylinder pressures of the direct-injected V8 will erode the electrode rapidly, leading to misfires and poor fuel economy long before the 97,500-mile interval. Furthermore, the correct heat range is vital to prevent pre-ignition (pinging) while running hot enough to burn off carbon deposits. Stick to ACDelco, NGK Laser Iridium, or Denso Iridium Long Life.

How to gap a spark plug

Most premium iridium spark plugs, like the ACDelco 41-114, come pre-gapped from the factory at 0.040 inches. However, you must always verify the gap before installation in case the plug was dropped during shipping.

1. Use the right tool: Use a wire-style gap gauge or a specialized feeler gauge rather than a cheap coin-style gauge, which can easily damage the fragile iridium tip.
2. Check the gap: Carefully slide the 0.040" (1.0 mm) gauge between the center and ground electrode. It should pass through with a slight "drag."
3. Adjusting the gap: If the gap is too tight, use the bending tool on the gauge to gently pry the ground strap up. Never pry against the iridium center electrode—it is extremely brittle and will snap off. If the gap is too wide, gently tap the ground strap on a hard surface to close it.

Replacement procedure tips

Replacing plugs on the 2017 GMC Yukon is relatively straightforward, but the coil-on-plug architecture and tight engine bay require some finesse.

• Accessing the rear plugs: The passenger-side rear plug (Cylinder 8) is notoriously tight against the firewall. You will absolutely need a few different lengths of extensions and a high-quality universal joint (swivel socket) to reach it comfortably. Removing the passenger-side wheel and inner fender liner can also give you a straight shot at the rear plugs.
• The Anti-Seize debate: Modern ACDelco and NGK spark plugs feature a special nickel-plated zinc coating on the threads designed to prevent seizing in the aluminum cylinder heads. GM explicitly advises against using anti-seize compound. Adding anti-seize acts as a lubricant and can cause you to over-torque the plug, potentially damaging the cylinder head threads.
• Dielectric grease: Always apply a small pea-sized dab of dielectric grease inside the tip of the spark plug boot before pressing it onto the new plug. This prevents moisture intrusion, stops voltage leaks, and ensures the boot won't bake onto the ceramic insulator over the next 100,000 miles.

Known issues

While the GM EcoTec3 V8s do not suffer from the infamous two-piece spark plug breakage common on older Ford 3-valve engines, they do have a few quirks you should be aware of:

• Stuck Spark Plug Wires: The Yukon uses short ignition wires connecting the coil packs to the plugs. Due to the high under-hood temperatures, the metal heat shields and rubber boots frequently fuse to the spark plug ceramic. If you yank on the wire, the internal conductor will rip. It is highly recommended to purchase a new set of ACDelco spark plug wires before doing this job, as you will likely destroy a few during removal.
• Sensitive Coil Packs: The ignition coils on the 5.3L and 6.2L engines are highly sensitive to resistance changes. If a spark plug gap wears out too wide or if a cheap aftermarket plug is used, the increased electrical resistance can overheat and burn out the coil pack prematurely.

Need plugs replaced? Find a shop on Repairius.