2024 Volvo VNR Spark Plug Type & Gap

Quick Reference

Why the right plug matters

The 2024 Volvo VNR is exclusively offered with diesel engines (D11, D13, D13TC) in North America. Diesel engines do not use spark plugs for ignition. Instead, they rely on compression ignition, where air is highly compressed until it reaches a temperature hot enough to ignite the injected diesel fuel.

Therefore, all the information regarding spark plug types (iridium, platinum, copper), heat ranges, electrode materials, and gapping procedures is not applicable to your 2024 Volvo VNR. Choosing the "right" spark plug is typically critical for gasoline engines because it impacts combustion efficiency, fuel economy, emissions, and overall engine performance. A spark plug's heat range, for instance, determines how quickly heat is dissipated from the tip. Too hot, and pre-ignition can occur; too cold, and carbon fouling becomes a problem. The electrode material also affects longevity and ignition performance. Iridium and platinum plugs offer extended life and more consistent spark over time compared to conventional copper plugs.

However, for your diesel-powered VNR, these considerations are entirely irrelevant.

How to gap a spark plug

This section primarily applies to gasoline engines that utilize spark plugs. Since your 2024 Volvo VNR is equipped with a diesel engine, you do not need to gap spark plugs.

For gasoline engines, gapping a spark plug is the process of adjusting the distance between the center and ground electrodes to the manufacturer's precise specification. This is crucial for optimal spark delivery and combustion. A gap that is too wide can lead to misfires, while a gap that is too narrow can result in a weak spark and incomplete combustion. A wire-style gap gauge or a feeler gauge is typically used. The gauge should slide in with a slight, consistent drag. If adjustment is needed, the ground electrode is carefully bent with a gapping tool. Always avoid bending or prying on the center electrode or insulator.

Replacement procedure tips

As the 2024 Volvo VNR uses diesel engines, there are no spark plugs to replace. Therefore, tips for spark plug replacement, such as coil-on-plug removal, the anti-seize debate, and the application of dielectric grease, do not apply.

In a gasoline engine, the replacement procedure often involves removing the coil-on-plug (COP) assemblies, which deliver high-voltage current directly to each spark plug. Care must be taken to avoid damaging the coil or its electrical connector. The "anti-seize debate" refers to whether to apply anti-seize compound to spark plug threads. Some manufacturers recommend against it, as it can alter torque readings and potentially lead to over-tightening or heat transfer issues. Dielectric grease is often applied to the inside of the spark plug boot to prevent electrical arcing and aid in boot removal, but it should never be applied to the electrode ends.

Known issues

There are no known issues related to spark plugs for the 2024 Volvo VNR, as it operates on diesel compression ignition and does not use spark plugs.

For gasoline engines, some common spark plug-related issues can include: cracked porcelain insulators (leading to misfires and engine damage), broken plug shells (often seen with specific Ford 3-valve engine designs during removal), or premature wear due to improper heat range or engine conditions. Some advanced systems, like GM's ionization-sensing coils, use spark plug resistance to detect misfires, and improper spark plugs can interfere with these diagnostics.

Need plugs replaced? Find a shop on Repairius.