2023 International LT — Spark Plug Type & Gap

Quick reference

Why the right plug matters

For the 2023 International LT, spark plugs aren't applicable since diesel engines do not use spark plugs for ignition. Diesel engines rely on compression ignition, where the air in the cylinder is compressed to such a high degree that it increases in temperature enough to ignite the injected diesel fuel.

However, in typical gasoline engines, selecting the correct spark plug is vital for optimal performance, fuel efficiency, and engine longevity. The spark plug's heat range, electrode material, and gap all play critical roles.

• Heat Range: A spark plug's heat range refers to its ability to dissipate heat. A "hotter" plug dissipates heat more slowly, while a "colder" plug dissipates heat more quickly. Using a plug with the wrong heat range can lead to pre-ignition (if too hot) or fouling (if too cold).
• Electrode Metal: Different electrode materials offer varying levels of durability and performance:
  • Copper: Traditional and excellent conductors, but have the shortest lifespan.
  • Platinum: More durable than copper, offering longer service intervals.
  • Iridium: The most durable and expensive, providing the longest lifespan and best performance, often recommended for modern engines with longer service intervals.

How to gap a spark plug

While not relevant for the 2023 International LT, for gasoline engines, properly gapping a spark plug is crucial. The gap is the distance between the center and ground electrodes. An incorrect gap can lead to misfires, reduced fuel economy, and poor engine performance.

• Tools: Use a wire-type spark plug gapping tool for accurate measurements. Avoid using a ramp-style tool, especially on fine-wire iridium or platinum plugs, as it can damage the electrode.
• Adjusting the Gap: If adjustment is needed, gently bend the ground electrode. For larger gaps, use the gapping tool to pry it open. For smaller gaps, tap the ground electrode lightly on a hard, non-abrasive surface.

Replacement procedure tips

Since the 2023 International LT uses diesel engines, spark plug replacement procedures are not applicable. However, for a general understanding of gasoline engine spark plug replacement:

• Coil-on-Plug Removal: Many modern gasoline engines use coil-on-plug ignition systems. This means each spark plug has its own ignition coil directly mounted on top of it. Carefully disconnect the electrical connector and unbolt/remove the coil to access the spark plug.
• Anti-Seize Debate: While some technicians apply a small amount of anti-seize to spark plug threads, many spark plug manufacturers recommend against it. Modern plugs often have special coatings, and anti-seize can alter torque specifications, leading to over-tightening and potential plug or cylinder head damage. Always refer to the spark plug manufacturer's recommendations.
• 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 help prevent moisture intrusion and make future removal easier.

Known issues

There are no known spark plug-related issues for the 2023 International LT as it is equipped with diesel engines. Common spark plug issues like cracked porcelain or broken plug shells are typically associated with gasoline engines.

Need plugs replaced? Find a shop on Repairius.