2024 International LT Spark Plug Type & Gap

Quick reference

Why the right plug matters

For a vehicle like the 2024 International LT, which primarily uses diesel engines, the concept of "spark plugs" in the traditional sense doesn't apply. Diesel engines operate on compression ignition, meaning they ignite the fuel-air mixture by compressing it to a high temperature, rather than using an electrical spark from a spark plug.

However, it's crucial to understand why having the correct ignition components (or fuel injectors, in the case of a diesel) is vital for any internal combustion engine. The principles that make spark plugs critical for gasoline engines can be translated to the importance of properly functioning fuel injection and glow plugs (if applicable) in a diesel engine.

In gasoline engines, the spark plug is responsible for initiating combustion. Its design, including heat range, electrode material (iridium, platinum, or copper), and gap, directly impacts engine performance, fuel efficiency, and emissions.

• Heat Range: A spark plug's heat range determines how quickly it dissipates heat from the combustion chamber. A plug that's too hot can lead to pre-ignition and knocking, while a plug that's too cold can foul up with carbon deposits.
• Electrode Material: Different materials offer varying levels of durability and performance.
  • Copper: Excellent conductivity but wears fastest, typically used in older vehicles or specific performance applications for its strong spark.
  • Platinum/Double Platinum: More durable than copper, offering longer service intervals. Often found in modern engines.
  • Iridium: The most durable and expensive, providing the longest service life and most consistent spark. Common in high-performance and modern engines.

How to gap a spark plug

This section is not applicable to the 2024 International LT as it uses diesel engines, which do not have spark plugs. However, for general knowledge about gapping spark plugs in gasoline engines:

To gap a spark plug, you typically use a specialized spark plug gap tool. This tool, often a round disc with a tapered edge or a set of flat gauges, helps you precisely measure the distance between the center and ground electrodes. If the gap needs adjustment, you gently bend the ground electrode using the tool. It's crucial to avoid bending the center electrode or applying excessive force, as this can damage the plug.

Replacement procedure tips

As the 2024 International LT is equipped with diesel engines, there are no spark plugs to replace. Instead, maintenance typically involves fuel injector service, glow plug inspection (on some diesel engines for cold starts), and fuel filter changes. If you were working on a gasoline engine with coil-on-plug ignition, here are some general tips:

• Coil-on-Plug Removal: Carefully disconnect the electrical connector from each ignition coil. Then, gently twist and pull the coil straight up to remove it from the spark plug well. Avoid yanking on the wires.
• Anti-Seize Debate: There's ongoing debate about using anti-seize compound on spark plug threads. Many spark plug manufacturers recommend against it, stating that it can alter torque readings and lead to over-tightening. Follow the spark plug manufacturer's recommendations.
• Dielectric Grease on Boots: Applying a small amount of dielectric grease inside the spark plug boot (or onto the ceramic insulator of the plug) can help prevent moisture intrusion and make future removal easier. It also helps ensure good electrical insulation.

Known issues

The 2024 International LT, being a modern heavy-duty truck, is not known for "spark plug issues" in the way gasoline engines might be. Common issues in diesel engines revolve around different components:

• Fuel Injector Longevity: Diesel injectors operate under immense pressure and precision, and their lifespan can be affected by fuel quality and maintenance. Clogged or failing injectors can lead to rough running, reduced power, and increased emissions.
• Exhaust Aftertreatment Systems: Modern diesels incorporate complex systems like Diesel Particulate Filters (DPF) and Selective Catalytic Reduction (SCR) to reduce emissions. These systems require specific maintenance and can experience issues if not properly cared for.
• Glow Plug Failure: In colder climates, glow plugs assist with starting diesel engines. Failure of one or more glow plugs can make cold starts difficult.

Need plugs replaced? Find a shop on Repairius.