2025 Jeep Wrangler Spark Plug Specs & Replacement Guide

As an ASE-certified master technician, I’ve wrenched on more Jeeps than I can count. The 2025 Jeep Wrangler continues its legacy as a rugged off-roader, but whether you are crawling over Moab’s red rocks or just commuting to work, your engine needs reliable spark. Modern Wranglers rely on highly efficient coil-on-plug (COP) ignition systems, and choosing the right spark plugs—and installing them correctly—is critical for maintaining power, fuel economy, and emissions standards.

Here is your comprehensive guide to the spark plug specifications, gaps, and replacement procedures for the 2025 Jeep Wrangler.

Quick reference

Note: Always verify part numbers with your VIN, as mid-year production changes can occur.

Why the right plug matters

Modern engines like the 2.0L Turbo and 3.6L Pentastar are incredibly sensitive to spark plug design. The right plug isn't just about making a spark; it's about making the right spark at the right temperature.

• Heat Range: Installing a plug with the wrong heat range can cause severe engine damage. A plug that is too hot will cause pre-ignition (pinging), while a plug that is too cold will foul out with carbon deposits. Stick to the OEM heat range.
• Electrode Material: The 2025 Wrangler strictly calls for Iridium spark plugs. Iridium is much harder and more durable than platinum or traditional copper. This allows for a finer wire center electrode, which concentrates the electrical charge for a more efficient spark while surviving the high cylinder pressures of the 2.0L turbo and the long 100k-mile service intervals of the naturally aspirated engines. Do not downgrade to platinum or copper.

How to gap a spark plug

Even though most iridium spark plugs come pre-gapped from the factory, an ASE master tech will always tell you to "trust, but verify." Shipping and handling can easily bump the ground strap and close the gap.

1. Use the Right Tool: Never use a cheap coin-style gauge on an iridium plug. The center electrode is fragile and easily snapped. Use a wire-type gauge or a specialized feeler gauge.
2. Measure Gently: Slide the wire gauge through the gap. It should slide through with a slight "drag."
3. Adjusting the Gap: If the gap needs adjustment, use a spark plug gapping tool that bends the ground strap by hooking onto it. Never pry against the fragile iridium center electrode. Lightly bend the strap up to open the gap, or tap it gently on a wooden workbench to close it. Re-measure until you hit the precise spec (e.g., 0.031" for the 2.0L).

Replacement procedure tips

Replacing plugs on a 2025 Wrangler requires a bit of patience, especially depending on your engine layout.

• Accessing the 3.6L V6: The driver's side bank is notoriously difficult to access because the upper intake manifold (plenum) partially covers it. You will need to remove the upper intake manifold to access the coils and plugs on that side safely. Make sure you buy a new set of upper intake manifold gaskets before starting the job!
• Coil-on-Plug Handling: The 2025 Wrangler uses COP ignition. When removing the ignition coils, twist the boot slightly before pulling straight up to avoid tearing the rubber boot.
• The Anti-Seize Debate: NGK and modern Mopar spark plugs feature a specialized trivalent metal plating that prevents seizing in the aluminum cylinder heads. Therefore, do not use anti-seize on the threads. Adding anti-seize acts as a lubricant, which alters your torque values and can easily lead to over-tightening and stripping the aluminum threads.
• Dielectric Grease: Apply a pea-sized amount of dielectric grease to the inside tip of the coil boot. This prevents moisture intrusion (vital for off-roading Wranglers!) and prevents the boot from welding itself to the ceramic of the new spark plug.

Known issues

While the modern Jeep engines don't suffer from the infamous 2-piece spark plug breakage seen in early 2000s Ford 3-valves, there are still things to watch out for.

• 2.0L Turbo Carbon Tracking: Because the 2.0L operates under high boost pressures, the ignition system works overtime. If the spark plug gap wears too wide, the electrical charge can seek the path of least resistance down the outside of the plug, causing "carbon tracking" (a black lightning-bolt scar on the white porcelain). If you see this, you must replace both the spark plug and the ignition coil boot, or the misfire will immediately return.
• 4xe PHEV Specifics: The 4xe plug replacement interval is heavily dependent on how often the gas engine runs, but Jeep still mandates replacement by the scheduled mileage/time limit to prevent the plugs from seizing in the head over years of short-cycling.

Need plugs replaced? Find a shop on Repairius.