2017 GMC Acadia Spark Plug Type & Gap

Quick Reference

Why the right plug matters

Choosing the correct spark plug for your 2017 GMC Acadia is crucial for optimal engine performance, fuel efficiency, and longevity. Spark plugs are designed with specific heat ranges and electrode materials to match your engine's requirements.

Heat Range: A spark plug's heat range refers to its ability to dissipate heat from the combustion chamber. A "hotter" plug dissipates heat slower and is suitable for engines that run at lower temperatures, while a "colder" plug dissipates heat faster and is used in high-performance or high-temperature engines. Using the wrong heat range can lead to pre-ignition, detonation, or premature plug fouling.

Electrode Metal:

• Iridium: This is the most common and recommended material for modern vehicles like your Acadia. Iridium plugs offer exceptional durability and a long lifespan due to their extremely hard and corrosion-resistant properties. They provide a very fine center electrode, leading to a more focused and powerful spark.
• Platinum: Platinum plugs are a step up from copper, offering better longevity and performance. They typically feature a platinum-tipped center electrode. While durable, they don't quite match the lifespan or efficiency of iridium.
• Copper: While excellent conductors, copper plugs have a shorter lifespan due to the softness of the material and their larger electrode requiring more voltage to jump the gap. They are rarely specified for modern engines with advanced ignition systems due to their rapid wear.

For your 2017 GMC Acadia, both the 2.5L I4 and 3.6L V6 engines are designed for long-life iridium spark plugs, as indicated by the extended replacement interval.

How to gap a spark plug

Properly gapping a spark plug ensures the ideal distance for the spark to jump between the electrodes, creating an efficient and complete combustion event. While most iridium plugs come pre-gapped from the factory, it's always a good practice to verify the gap before installation, especially if they have been dropped or handled roughly. However, exercise extreme caution when gapping iridium or platinum plugs. Their fine electrodes are brittle and can be easily damaged.

To check the gap:

1. Use a wire-type spark plug gapping tool. Avoid using disc-style gap tools, as they can damage fine-wire electrodes.
2. Carefully slide the correct feeler gauge wire into the gap between the center and ground electrodes.
3. It should slide in with a slight drag. If adjustment is needed, gently bend only the ground electrode using the adjustment tool on the gapper. Never attempt to bend the center electrode.
4. Recheck the gap to ensure it matches the specified dimension (0.043 in / 1.1 mm for your Acadia).

Replacement procedure tips

Replacing spark plugs on your 2017 GMC Acadia involves working with a coil-on-plug ignition system. Here are some tips to ensure a smooth replacement:

1. Safety First: Always work on a cool engine. Disconnect the negative battery terminal before starting any work.
2. Coil-on-Plug Removal: Each spark plug has its own ignition coil mounted directly on top of it. Carefully disconnect the electrical connector by depressing the release tab and pulling. Then, gently twist and pull upwards on the coil to remove it from the spark plug well.
3. Cleanliness: Before removing the old spark plugs, it's a good idea to blow out any debris around the spark plug wells with compressed air. This prevents dirt and grime from falling into the combustion chambers once the plugs are removed.
4. Anti-Seize Debate: There's ongoing debate regarding the use of anti-seize on spark plug threads. Most modern spark plugs, especially those with nickel-plated shells, do not require anti-seize. In fact, applying it can lead to over-torquing and potential damage to the cylinder head threads or spark plug insulator. If you choose to use it, apply a very thin amount to the threads only, and reduce the torque specification by approximately 10-20% to compensate for the lubrication.
5. Dielectric Grease on Boots: Apply a small amount of dielectric grease inside the spark plug boot (the part that connects to the top of the spark plug). This helps seal out moisture, prevents corrosion, and makes future removal easier. Be careful not to get grease on the electrical contacts.
6. Torque Matters: Always follow the manufacturer's torque specifications (13 lb-ft / 18 Nm). Over-tightening can damage the spark plug or the cylinder head threads, while under-tightening can lead to combustion gas leakage and overheating of the spark plug.

Known Issues

Fortunately, the 2017 GMC Acadia's engines (2.5L LCV and 3.6L LGX) do not have widespread, notorious spark plug-related issues akin to the Ford 3-valve 2-piece plug breakage. These engines are generally robust, and with proper maintenance and the correct spark plugs installed, you should not encounter any unusual problems.

Need plugs replaced? Find a shop on Repairius.