2018 Nissan Frontier — Spark Plug Type & Gap

Quick reference

Why the right plug matters

Choosing the correct spark plug for your 2018 Nissan Frontier is crucial for optimal engine performance, fuel efficiency, and longevity. Spark plugs are responsible for igniting the air-fuel mixture in your engine's cylinders, and an incorrect plug can lead to misfires, reduced power, and increased emissions.

Heat range

Spark plugs are designed with a specific "heat range," which refers to their ability to dissipate heat from the combustion chamber. A plug that's too "cold" (dissipates heat too quickly) can lead to fouled plugs and misfires, especially in stop-and-go driving. A plug that's too "hot" (dissipates heat too slowly) can cause pre-ignition or detonation, which can severely damage engine components. Always use the specified heat range for your engine.

Electrode metal

Modern spark plugs come with different electrode materials, each with its own advantages and disadvantages:

• Iridium: These are the most durable and long-lasting plugs, offering excellent performance and fuel economy. Iridium is a very hard and dense metal, allowing for a finer center electrode that requires less voltage to fire. Both the 2.5L I4 and 4.0L V6 in your Frontier use iridium-tipped plugs as OEM.
• Platinum: Platinum plugs are also long-lasting and offer good performance. They are typically less expensive than iridium plugs but may not last quite as long.
• Copper: Copper plugs have a larger center electrode and are excellent conductors of electricity. However, they wear out much faster than iridium or platinum plugs and are generally not recommended for modern engines designed for longer-lasting materials.

How to gap a spark plug

The gap between the center and ground electrodes of a spark plug is critical for proper ignition. Too wide, and the spark may not jump consistently; too narrow, and the spark may be too weak. For your 2018 Nissan Frontier, the recommended gap is 0.043 inches (1.1 mm).

To gap a spark plug, you'll need a spark plug gapping tool. A wire-style gauge is often preferred for iridium and platinum plugs to avoid damaging the fine electrodes. Carefully insert the correct wire gauge between the electrodes. If the gap is too narrow, you can gently bend the ground electrode outwards with the gapping tool. If it's too wide, carefully tap the ground electrode on a hard surface to close the gap. Always re-check the gap after any adjustment.

Replacement procedure tips

Both the 2.5L I4 and 4.0L V6 engines in the 2018 Nissan Frontier utilize a coil-on-plug (COP) ignition system. This means each spark plug has its own ignition coil directly mounted on top of it, eliminating the need for spark plug wires.

Coil-on-plug removal

1. Disconnect the negative battery terminal: Always disconnect the battery before working on electrical components.
2. Remove engine covers (if applicable): Some engines have decorative plastic covers that need to be removed to access the coils.
3. Disconnect electrical connectors: Carefully unplug the electrical connector from each ignition coil. Be gentle, as these plastic connectors can become brittle with age.
4. Remove coil hold-down bolts: Most coils are held in place by a single bolt. Remove these bolts.
5. Remove the ignition coil: Gently twist and pull the ignition coil upwards to remove it from the spark plug well. If it's stuck, a little lubricant around the boot can help, but avoid spraying directly into the well.

Anti-seize debate

There's a long-standing debate about whether to use anti-seize compound on spark plug threads. For modern spark plugs with nickel-plated shells, manufacturers like NGK explicitly state that anti-seize is not recommended. The nickel plating provides sufficient corrosion resistance and acts as a lubricant. Using anti-seize can act as an insulator, potentially affecting the torque specification and leading to over-tightening, which can damage the spark plug or cylinder head threads.

Dielectric grease on boots

Applying a small amount of dielectric grease inside the spark plug boot (the part that connects to the top of the spark plug) can be beneficial. Dielectric grease creates a moisture-resistant seal, prevents corrosion, and makes future removal easier. Only use a thin film; too much can attract dirt and debris.

Known issues

Fortunately, the 2018 Nissan Frontier, particularly with its common VQ40DE and QR25DE engines, does not have widely reported or notorious spark plug-related issues akin to the Ford 3-valve modular engines with their multi-piece spark plug breakage. Using the correct OEM or equivalent iridium plugs and following recommended torque specifications will typically result in trouble-free operation for the entire service interval.

Need plugs replaced? Find a shop on Repairius.