2015 Ford F-250 Super Duty Spark Plug Type & Gap

Quick reference

Why the right plug matters

Choosing the correct spark plug for your 2015 Ford F-250 Super Duty is crucial for optimal engine performance, fuel efficiency, and longevity. Spark plugs are not "one size fits all" components; they are engineered with specific heat ranges, electrode materials, and designs to match the unique characteristics of each engine.

The heat range of a spark plug refers to its ability to dissipate heat from the combustion chamber. A "hotter" plug dissipates heat more slowly, while a "colder" plug dissipates it more quickly. An incorrect heat range can lead to pre-ignition (where the fuel ignites before the spark) or fouling (where carbon deposits build up on the plug), both of which can significantly damage your engine.

Electrode materials also play a significant role. Most modern vehicles, including the 2015 F-250, come with iridium or platinum spark plugs from the factory. These precious metals are incredibly durable and resistant to wear, allowing for extended replacement intervals (typically 100,000 miles or more). Copper spark plugs, while offering excellent conductivity, wear out much faster and require more frequent replacement (every 30,000 miles or so). While copper plugs might be cheaper upfront, the labor costs for more frequent changes often outweigh the initial savings.

How to gap a spark plug

Even though many modern iridium and platinum spark plugs come "pre-gapped" from the factory, it's always a good practice to double-check the gap before installation. The gap is the distance between the center and ground electrodes. An incorrect gap can lead to misfires, reduced power, and decreased fuel economy.

To gap a spark plug, you'll need a specialized gauge tool. There are two common types: a round wire gauge or a feeler gauge. For precious metal plugs, it's highly recommended to use a wire-style gauge to avoid damaging the delicate electrode. Gently slide the appropriate size wire through the gap. If the wire slides through with slight resistance, the gap is correct. If it's too tight, you can carefully bend the ground electrode outwards using the gapping tool's lever. If it's too wide, gently tap the ground electrode on a solid surface until the gap is correct. Always adjust the ground electrode only; never attempt to bend the center electrode.

Replacement procedure tips

Replacing spark plugs on your 2015 Ford F-250 Super Duty 6.2L V8 engine is a manageable DIY task, but a few tips can make the process smoother:

• Coil-on-plug removal: Your F-250 uses a coil-on-plug (COP) ignition system, meaning each spark plug has its own individual ignition coil. To access the spark plugs, you'll need to disconnect the electrical connector from each coil and then remove the bolt holding the coil in place. Gently twist and pull the coil straight up to remove it from the spark plug well. Avoid pulling on the wire harness.
• Anti-seize debate: There's ongoing debate regarding the use of anti-seize compound on spark plug threads. Ford, like many manufacturers, recommends against using it on modern plugs with nickel-plated shells, as it can alter the torque readings and potentially lead to overtightening. If you choose to use it, apply a very thin layer and reduce the torque specification by approximately 10-15%. However, for most applications, it's best to follow the manufacturer's recommendation and install the plugs dry.
• Dielectric grease on boots: Apply a small amount of dielectric grease inside the spark plug boot (the rubber part that connects the coil to the plug). This helps to prevent moisture intrusion, eases future removal, and ensures a good electrical connection.
• Torque specs are critical: As noted in the quick reference table, it's crucial to tighten spark plugs to the manufacturer-specified torque (8-10 lb-ft or 11-14 Nm for the 6.2L V8). Overtightening can damage the spark plug threads in the cylinder head, a costly repair. Undertightening can lead to compression leaks and potentially allow the plug to back out.

Known issues

Fortunately, the 6.2L V8 engine in the 2015 Ford F-250 Super Duty is not known for the infamous 2-piece spark plug issues that plagued earlier Ford 3-valve modular engines. These engines generally offer a straightforward spark plug replacement experience.

Need plugs replaced? Find a shop on Repairius.