2019 Jeep Wrangler Spark Plug Type and Gap

Quick Reference

Why the right plug matters

Selecting the correct spark plug for your 2019 Jeep Wrangler is crucial for maintaining optimal engine performance, fuel economy, and longevity. The two primary engine options, the 2.0L I-4 Turbo and the 3.6L V6 Pentastar, utilize different spark plugs tailored to their specific combustion characteristics. Key factors to consider are heat range, electrode material, and design.

• Heat Range: This refers to the spark plug's ability to dissipate heat. A plug that is too "hot" can lead to pre-ignition, while a "cold" plug may foul more easily. The turbocharged 2.0L engine requires a colder plug to handle the increased cylinder pressures and temperatures, while the naturally aspirated 3.6L V6 uses a hotter plug.

• Electrode Material: Modern engines, including those in the 2019 Wrangler, are equipped with long-life iridium-tipped spark plugs. While more expensive than their platinum or copper counterparts, iridium plugs offer a significantly longer service interval (up to 100,000 miles) and a more consistent spark, thanks to their fine-wire center electrode. This translates to better fuel efficiency and lower emissions over the life of the plug.

How to gap a spark plug

Properly gapping your spark plugs is a critical step in a tune-up. The "gap" is the distance between the center and ground electrodes, and it must be set precisely to ensure a strong, consistent spark. For the 2019 Wrangler, the 2.0L requires a 0.031-inch gap, while the 3.6L needs a 0.043-inch gap.

1. Use a Feeler Gauge or Wire-Type Tool: These tools have wires or blades of varying thicknesses to measure the gap. Do not use a ramp-style gauge, as it can damage the delicate iridium tip.

2. Check the Gap: Gently slide the correct wire or blade between the electrodes. It should have a slight drag.

3. Adjust if Necessary: If the gap is too wide, gently tap the ground electrode on a clean, hard surface. If it's too narrow, use the tool to carefully bend the ground electrode away from the center electrode. Always bend the ground electrode, never the center one.

Replacement procedure tips

Both the 2.0L and 3.6L engines in the 2019 Wrangler feature a coil-on-plug ignition system, which simplifies the replacement process compared to older distributor-based systems.

• Coil-on-Plug Removal: Each spark plug has its own ignition coil directly on top of it. To access the plug, you'll first need to disconnect the electrical connector and then unbolt the coil (typically a single 10mm bolt). Gently twist and pull the coil straight up to remove it.

• Anti-Seize Debate: While anti-seize compound was once a staple of spark plug replacement, many modern plugs, including the OEM Mopar and NGK plugs for the Wrangler, have a special nickel plating that prevents them from seizing in the cylinder head. Applying anti-seize can alter the torque reading, leading to over-tightening. It's generally recommended to install these plugs clean and dry.

• Dielectric Grease: Apply a small amount of dielectric grease to the inside of the spark plug boot before reinstalling the ignition coil. This helps to seal out moisture and prevent the boot from sticking to the spark plug porcelain, making future removal easier.

Known issues

While the 2019 Jeep Wrangler engines are generally robust, there are no widespread, recurring issues related to spark plug failure like the infamous Ford 3-valve two-piece plug breakage. The use of modern, high-quality iridium plugs and a one-piece shell design has made such problems a thing of the past for these powertrains.

It is, however, always important to use a quality spark plug socket with a rubber insert and to tighten the plugs to the specified torque. Over-torquing can lead to cracked porcelain or damaged threads in the cylinder head, resulting in costly repairs.

Need plugs replaced? Find a shop on Repairius.