2015 Nissan Altima Spark Plug Type & Gap

Quick reference

Why the right plug matters

Choosing the correct spark plug for your 2015 Nissan Altima is more critical than you might think. Spark plugs are not "one-size-fits-all" components. Several factors, including heat range, electrode materials, and design, are carefully engineered by the manufacturer to work in harmony with your specific engine.

Heat Range: This refers to the plug's ability to dissipate heat from the combustion chamber. A plug that runs too "hot" can lead to pre-ignition and detonation, causing significant engine damage. Conversely, a plug that runs too "cold" can accumulate carbon deposits, leading to misfires and poor fuel economy. OEM plugs are designed with the optimal heat range for your Altima's engine to maintain consistent performance and longevity.

Electrode Metal: Modern spark plugs utilize various electrode materials, each with its own advantages:

• Iridium: This is the most common material for long-life spark plugs, like those recommended for your Altima. Iridium is extremely hard and has a very high melting point, allowing for very fine electrodes that produce a strong, focused spark. This leads to better fuel efficiency, reduced emissions, and extended replacement intervals, often exceeding 100,000 miles.
• Platinum: Platinum plugs offer good durability and improved performance over traditional copper plugs. They typically have a platinum disc welded to the center electrode and sometimes the ground electrode. While still a good choice, they generally don't last as long as iridium plugs in modern applications.
• Copper: While still used in some older or high-performance, non-forced induction applications, copper plugs have a much shorter lifespan due to copper's lower melting point. They are not recommended for your 2015 Nissan Altima, as the engine requires the extended life and performance benefits of iridium plugs.

Using the wrong type of spark plug can lead to various problems, including misfires, reduced fuel economy, decreased engine power, and even catalytic converter damage over time.

How to gap a spark plug

Modern iridium spark plugs, like those specified for your 2015 Nissan Altima, typically come pre-gapped from the factory. For iridium and platinum plugs, it's generally recommended NOT to adjust the gap unless absolutely necessary and with extreme caution. The fine wire electrodes are delicate and can be easily damaged. If you do need to check the gap, use a wire-style spark plug gap tool (NOT a ramp-style or coin-style gapping tool, as these can damage the fine electrode). If the gap is slightly off, you can carefully bend the ground electrode only, using minimal force. Never attempt to bend the center electrode.

For your 2015 Altima, the correct gap is 0.043 inches (1.1 mm). Always double-check this specification with a reliable service manual for your exact trim and engine combination.

Replacement procedure tips

Replacing spark plugs on your 2015 Nissan Altima is a manageable DIY task for those with some mechanical experience. Both the 2.5L I4 and 3.5L V6 engines utilize coil-on-plug (COP) ignition systems, meaning each spark plug has its own individual ignition coil mounted directly on top of it.

1. Preparation: Ensure the engine is cool before starting. Disconnect the negative battery terminal for safety.
2. Coil-on-Plug Removal: Carefully disconnect the electrical connector from each ignition coil. Then, unbolt the coil (usually a 10mm or 12mm bolt) and gently pull it straight up to remove it from the spark plug well. Avoid yanking on the wires.
3. Spark Plug Removal: Use a dedicated spark plug socket (typically a 5/8-inch, with a rubber insert to protect the plug porcelain) and a long extension. Loosen each plug counter-clockwise. Be careful not to cross-thread during removal or installation.
4. Anti-Seize Debate: There is ongoing debate about using anti-seize on spark plug threads. Nissan often recommends against it for iridium plugs, as it can alter the torque readings and potentially lead to over-tightening or damage. The plugs usually come with a special coating on the threads. If you choose to use it, apply a very thin amount to the threads only, avoiding the electrodes, and reduce your torque setting by about 10-20%.
5. Dielectric Grease: Apply a small amount of dielectric grease inside the spark plug boot (the end of the coil that connects to the plug). This helps seal out moisture, prevents corrosion, and makes future removal easier. Do not apply it to the spark plug electrodes.
6. Installation: Hand-thread the new spark plugs into the cylinder head to avoid cross-threading. Once finger-tight, use a torque wrench to tighten them to the specified torque value (14-22 lb-ft / 19-30 Nm). Over-tightening can damage the cylinder head threads or the spark plug itself, while under-tightening can cause misfires or allow combustion gases to escape.
7. Reassembly: Reinstall the ignition coils, ensuring they seat properly over the spark plugs. Reconnect the electrical connectors and tighten the coil mounting bolts. Reconnect the battery.

Known issues

The 2015 Nissan Altima, across both its 2.5L QR25DE and 3.5L VQ35DE engines, does not have any widespread, engine-specific "known issues" related to spark plugs, such as the infamous two-piece plug breakage seen in some Ford 3-valve engines or unique ionization-sensing coil problems like those on certain GM 5.3L engines. As long as the correct iridium-tipped plugs are used and replaced at the factory-recommended interval, and proper installation procedures are followed, the spark plug system is generally reliable.

Need plugs replaced? Find a shop on Repairius.