2017 Ford Explorer Spark Plug Guide

Quick Reference: 2017 Ford Explorer Spark Plugs

Why the Right Spark Plug Matters

Selecting the correct spark plug is critical for engine performance, efficiency, and longevity. It’s not just about finding a plug that fits; the engineering behind it matters.

• Heat Range: This is a plug's ability to dissipate heat. An incorrect heat range can lead to pre-ignition (too hot) or fouling (too cold). The factory-specified plugs are designed for the precise thermal environment of your Explorer’s engine, whether it’s the high-combustion pressures of an EcoBoost or the natural aspiration of the Ti-VCT.

• Electrode Material: Modern engines, like those in your 2017 Explorer, almost exclusively use fine-wire iridium or platinum center electrodes. These precious metals are much harder and have a higher melting point than traditional copper. This allows them to last up to 100,000 miles and maintain a precise, consistent spark, which is essential for complete combustion and emissions control. Copper plugs are cheaper but have a much shorter lifespan (typically 20,000-30,000 miles) and are not recommended for this vehicle.

How to Gap a Spark Plug

Even though most modern iridium plugs come pre-gapped, it is crucial to verify the gap before installation. Shipping and handling can easily close the gap.

1. Use the Right Tool: A feeler gauge or a wire-style gapping tool are the best choices. Avoid the old "coin-style" disc tools, as they can put pressure on the fine-wire electrode and damage it.
2. Check the Gap: Gently slide the correct wire or blade of your gauge between the center and ground electrodes. It should slide through with a slight drag. If it’s too loose or won’t fit, the gap needs adjustment.
3. Adjust Carefully: To adjust, gently bend only the ground strap (the curved piece of metal over the center electrode). Use the adjustment slot on your gapping tool. Never pry against or put pressure on the center electrode or the delicate porcelain insulator.

Replacement Procedure Tips

The 2017 Explorer uses a modern coil-on-plug (COP) ignition system, which places an individual ignition coil directly onto each spark plug. This eliminates the need for a distributor and spark plug wires.

• Coil-on-Plug Removal: After removing the engine cover, use an 8mm (or appropriately sized) socket to undo the bolt holding the coil in place. Gently twist and pull the coil straight up to remove it. The rubber boot can sometimes create a seal, requiring a bit of wiggling force.

• The Anti-Seize Debate: This is a hotly debated topic. Ford and spark plug manufacturers like NGK often recommend against using anti-seize on the plug threads of modern engines. The reasoning is that the plating on the plug shells already has anti-corrosive properties, and adding a lubricant can cause you to over-torque the plug, potentially stretching the threads in the aluminum cylinder head. If you do use it, use a tiny amount and reduce the torque spec by about 15-20%.

• Dielectric Grease: It is highly recommended to apply a small amount of dielectric grease to the inside of the ignition coil boot before reinstalling it. This prevents the boot from getting stuck to the spark plug porcelain, makes future removal easier, and helps seal out moisture that can cause a misfire.

Known Issues

While the 2017 model year is free of the most infamous Ford spark plug issues, it's worth knowing the history. Earlier Ford 3-valve modular engines (like the 5.4L V8) used a two-piece spark plug design that was notorious for breaking during removal, leaving the lower shell seized in the cylinder head. Thankfully, the engines in your 2017 Explorer use a conventional, robust one-piece plug design, and this breakage issue is not a concern.

Need plugs replaced? Find a shop on Repairius.