2021 Ford Ranger Spark Plug Type & Gap

Quick reference

Why the right plug matters

Choosing the correct spark plug for your 2021 Ford Ranger's 2.3L EcoBoost engine is crucial for optimal performance, fuel efficiency, and engine longevity. Spark plugs are not a "one size fits all" component. Various factors, including heat range, electrode material, and gap, are carefully engineered for your specific engine.

The heat range of a spark plug dictates how effectively it dissipates heat from the combustion chamber. A plug that runs too hot can lead to pre-ignition and engine damage, while a plug that runs too cold can cause fouling and misfires. The factory-specified plug has the ideal heat range for your Ranger's engine.

Electrode metal also plays a significant role. The 2021 Ford Ranger 2.3L EcoBoost typically uses iridium spark plugs. Iridium is an extremely hard and durable metal, allowing for a finer center electrode. This finer electrode concentrates the electrical charge, leading to a more consistent and powerful spark. Iridium plugs offer superior longevity and performance compared to older platinum or copper plugs, which is why your Ranger's plugs have a 100,000-mile replacement interval. Platinum plugs offered a good balance of performance and durability before iridium became prevalent, while copper plugs, though excellent conductors, have a much shorter lifespan and are typically found in older or performance applications where frequent replacement isn't an issue.

How to gap a spark plug

The spark plug gap is the distance between the center and ground electrodes. This gap is critical for a strong and consistent spark. While many modern iridium spark plugs come pre-gapped from the factory, it's always a good idea to double-check and adjust if necessary, especially if you're not using a Motorcraft plug.

You will need a spark plug gapping tool, commonly a wire-type gauge or a ramp-style gauge. For the 2.3L EcoBoost, the recommended gap is 0.028-0.031 inches (0.70-0.78 mm). If the gap is too small, you can carefully widen it by gently bending the ground electrode with the gapping tool. If the gap is too large, you can tap the ground electrode lightly on a hard surface to close it. Be extremely careful not to touch or damage the fine iridium center electrode, as it is very delicate.

Replacement procedure tips

Replacing the spark plugs on your 2021 Ford Ranger 2.3L EcoBoost is a straightforward process, but a few tips can make it smoother:

• Cool Engine: Always replace spark plugs when the engine is cool. This prevents cross-threading issues and reduces the risk of damaging the cylinder head threads.
• Coil-on-Plug Removal: Your Ranger uses a coil-on-plug (COP) ignition system. This means each spark plug has its own ignition coil directly mounted on top of it. To access the spark plugs, you'll need to disconnect the electrical connector from each coil and then remove the small bolt holding the coil in place. Gently twist and pull the coil straight up to remove it. Avoid prying, as this can damage the coil or its boot.
• Anti-Seize Debate: There's ongoing debate about using anti-seize compound on spark plug threads. For spark plugs with nickel-plated shells, like many modern plugs, anti-seize is generally not recommended as it can alter the torque readings and potentially lead to over-tightening. Follow the spark plug manufacturer's recommendations. If you choose to use it, apply a very thin amount to the threads, avoiding the electrode tip.
• Dielectric Grease: It's a good idea to apply a small amount of dielectric grease inside the spark plug boot (the part that connects to the coil). This helps seal out moisture, prevents corrosion, and makes future removal easier. Be careful not to get dielectric grease on the spark plug electrodes.
• Torque Wrench: Always use a torque wrench to tighten spark plugs to the specified 11 lb-ft (15 Nm). Over-tightening can damage the spark plug and cylinder head threads, while under-tightening can lead to compression leaks and premature plug wear.
• One at a Time: Replace one spark plug at a time to avoid mixing up ignition coil connectors or dropping debris into an open cylinder.

Known issues

Fortunately, the 2021 Ford Ranger's 2.3L EcoBoost engine is not known for specific common spark plug issues like the infamous two-piece spark plug breakage seen in some older Ford 3-valve engines. Sticking to the recommended Motorcraft spark plugs and following the proper replacement procedures should ensure trouble-free operation.

Need plugs replaced? Find a shop on Repairius.