2023 Jeep Grand Cherokee — Spark Plug Type, Gap & Torque

Quick reference

Note: Always confirm the exact Mopar plug part number by VIN or build sheet. Jeep sources plugs under Mopar; the manufacturing supplier may be NGK or another OE vendor depending on engine and production date.

Why the right plug matters

• Heat range: Too hot a plug can cause pre-ignition under load; too cold can foul at idle and short trips. Each engine above has a specific heat range that must be matched—don’t “step colder” unless you have calibrated tuning and data.
• Electrode material:
  • Iridium: Fine-wire iridium is OE for the 3.6L and 2.0T. It offers strong spark at lower voltage, better resistance to gap erosion, and 60k–100k service life.
  • Platinum: Middle ground for longevity; not commonly specified on these engines from the factory.
  • Copper/nickel: Excellent conductor and low cost, but shorter life (often 30k–60k). Some HEMI applications still specify copper plugs and use 16 total (two per cylinder).
• Don’t mix types: Use a matched set of the exact specified plug type and heat range. Mixing materials or heat ranges can cause drivability issues and misfire counts.

How to gap a spark plug

• Use a wire- or feeler-style gauge. Coin/step gauges can bend ground straps unevenly on fine-wire plugs.
• Check the factory spec above and on the under-hood emissions label. Many iridium plugs are factory pre-set—only correct if out of spec.
• If adjustment is needed, bend only the ground strap with a controlled, light tweak. Never pry against the center electrode or chip the iridium tip.
• Turbo engines (2.0T) are sensitive to gap. A gap that’s too wide can cause high-load misfires; too tight can hurt cold start quality.

Replacement procedure tips (2023 Grand Cherokee)

All engines use coil-on-plug ignition—no distributor.

General steps:

• Work on a cold engine. Blow out plug wells with compressed air before removing plugs.
• Disconnect the coil electrical connectors carefully; depress the tab fully to avoid breaking them. Remove coil hold-down bolts and lift coils straight up.
• Use a dedicated spark plug socket with a rubber insert or magnet. Break free, then spin out by hand.
• Inspect threads and seats. Do not use anti-seize on new, nickel-plated OE plugs; it alters torque values and can lead to over-tightening. If you must use it on older, unplated plugs, reduce torque by ~20–30%—but OE guidance is generally “no anti-seize.”
• Thread new plugs by hand until fully seated. Torque to spec (see table). Reinstall coils and apply a small dab of dielectric grease inside each boot to ease future service and help seal out moisture.

Engine-specific notes:

• 3.6L Pentastar V6: Straightforward access in the WL chassis. Verify gap ~0.043 in. Typical torque 13 lb-ft/18 Nm into aluminum heads.
• 2.0L Turbo 4xe: Fine-wire iridium plugs—avoid aggressive re-gapping. Keep gap in the narrower 0.024–0.028 in range to prevent boost/load misfire. Use care with high-voltage connectors near the hybrid components; follow battery disconnect procedures if required by service manual.
• 5.7L HEMI V8 (if equipped on Grand Cherokee L): There are 16 plugs (two per cylinder). Work methodically, one cylinder at a time. Inspect coil boots closely for carbon tracking; replace as needed. Torque remains modest at 13 lb-ft/18 Nm.

Known issues (what is and isn’t applicable)

• 3.6L Pentastar: Misfires are more commonly related to coil boots or, in some cases, valvetrain lifter issues—not plug breakage. Oil in plug tubes from aging valve cover gaskets can cause misfire; address leaks before replacing coils/plugs.
• 2.0L Turbo 4xe: Sensitive to plug gap and heat range under boost. Wide gaps or the wrong heat range can trigger P0300-series misfires at high load.
• 5.7L HEMI: Remember there are 16 plugs; missed plugs or uneven torque can create persistent single-cylinder misfires.
• Not applicable here: Ford 3-valve 5.4L/4.6L two-piece plug breakage and GM 5.3L ion-sensing coil peculiarities do not apply to the 2023 Grand Cherokee powertrains.

Need plugs replaced? Find a shop on Repairius.