2014 Kenworth W900 Spark Plug Type & Gap

Quick reference

Why the right plug matters

Choosing the correct spark plug for your 2014 Kenworth W900 is crucial for optimal engine performance, fuel efficiency, and emissions. However, it's important to note that the Kenworth W900, especially models from 2014, primarily utilizes diesel engines such as the Cummins ISX15 and the PACCAR MX-13. Diesel engines do not use spark plugs. Instead, they rely on compression ignition, where air is compressed to a high temperature, and then fuel is injected, igniting spontaneously.

Therefore, discussions about spark plug heat range, electrode material (iridium, platinum, or copper), and gapping procedures are not applicable to the main engine options found in a 2014 Kenworth W900.

How to gap a spark plug

This section is not applicable to the 2014 Kenworth W900 as its primary diesel engines do not use spark plugs. In a gasoline engine, gapping a spark plug involves using a dedicated gap gauge to ensure the precise distance between the center and ground electrodes. This gap is critical for a strong, consistent spark. Too small a gap can result in a weak spark and misfires, while too large a gap can stress the ignition system and also lead to misfires. When adjusting, gently bend the ground electrode using the tool, taking care not to touch the center electrode, especially on iridium or platinum plugs, as they are fragile.

Replacement procedure tips

Since the 2014 Kenworth W900 primarily uses diesel engines, there is no spark plug replacement procedure. Maintenance for these engines focuses on fuel injectors, glow plugs (if equipped, which operate differently than spark plugs), and other diesel-specific components.

For gasoline engines, general tips for spark plug replacement typically include:

• Coil-on-plug removal: Carefully disconnect and remove the coil-on-plug units. Apply a small amount of dielectric grease to the inside of the boot during reinstallation to prevent moisture intrusion and assist with future removal.
• Anti-seize debate: There is ongoing debate about using anti-seize on spark plug threads. Most modern spark plugs come with a special coating that prevents seizing, and applying additional anti-seize can alter torque readings, potentially leading to over-tightening. Always consult the spark plug manufacturer's recommendations.
• Dielectric grease on boots: Apply a thin layer of dielectric grease inside the spark plug boot to aid in sealing out moisture and making future removal easier. Avoid getting grease on the electrode tips.

Known issues

As the 2014 Kenworth W900 is equipped with diesel engines, common spark plug-related issues such as cracked porcelain on Ford 3-valve engines or broken plug shells are not applicable. Diesel engines have their own set of specific maintenance considerations and potential issues related to their fuel injection and compression ignition systems.

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