2017 Jeep Cherokee — Spark Plug Type, Gap & Torque

Quick reference

Note: FCA/Mopar used more than one supplier and superseded part numbers during this model year. To avoid the wrong reach or heat range, always confirm the exact OEM part number by VIN in the Mopar catalog or on the under-hood emissions label. Do not mix plug types within an engine.

Why the right plug matters

Choosing the correct spark plug is more than matching thread size. Heat range controls how quickly a plug sheds heat to the cylinder head. Too hot a plug risks pre-ignition; too cold can foul. The 2017 Cherokee’s aluminum heads and long-reach, 12 mm plugs are engineered around a specific heat range—stick with the factory spec.

Electrode material matters, too:

• Copper/nickel: Excellent conductivity, lower cost, but shorter life (often ~30k miles). Rarely specified for these engines.
• Platinum: Longer life than copper (often ~60k miles). Single- or double-platinum options exist.
• Iridium (fine-wire): Highest melting point, most stable gap, best for coil-on-plug ignition systems and extended intervals (~100k miles). This is the typical OEM technology on both the 2.4L and 3.2L.

Using the correct fine-wire iridium plug maintains efficient cold starts, stable idle, and reduces load on the ignition coils. Avoid downgrading to copper without adjusting service intervals.

How to gap a spark plug

Most OEM iridium plugs for the Cherokee are pre-gapped near 0.043 in (1.10 mm). Still, verify every plug:

1. Use a round-wire gap gauge, not a coin-style wedge that can damage fine-wire electrodes.
2. Check the gap. If an adjustment is needed, open the ground strap with a light bend from the strap base. Avoid prying on the precious-metal tip.
3. Re-check after any change. Consistency across all cylinders matters.

If a plug is significantly out of spec or the iridium tip looks damaged, replace it—don’t try to “fix” it.

Replacement procedure tips (2017 Cherokee)

Both engines use coil-on-plug ignition (no distributor). Work on a cold engine.

General steps:

• Disconnect the negative battery cable.
• Remove engine cover. Label connectors if needed.
• Blow out debris around coils with compressed air to prevent dirt from entering the cylinders.
• Unplug coils and remove the coil hold-down bolts. Gently twist coils to free the boots.
• Use a 5/8 in spark plug socket with extension. Break plugs loose smoothly—do not use impact tools.
• Thread new plugs by hand to avoid cross-threading, then torque to 13 lb-ft (18 Nm). If using anti-seize (not recommended on plated OEM plugs), reduce torque by ~20–30%.
• Apply a small dab of dielectric grease inside each coil boot and reinstall coils. Reconnect harnesses.

Engine-specific notes:

• 2.4L Tigershark I4: All four plugs are accessible from the top under the coil rail area. Straightforward service once the engine cover is off.
• 3.2L Pentastar V6: The rear bank (firewall side) coils/plugs are under the upper intake manifold. Plan to remove the intake plenum; replace the intake manifold gaskets and follow the factory torque sequence/spec when reinstalling. Budget extra time and check all vacuum and PCV connections during reassembly.

Anti-seize debate: Most OEM plugs for these engines have nickel-plated threads—install dry. Anti-seize can lead to over-torque and thread damage. If threads are corroded, chase with the proper tap and clean before installation rather than relying on compound.

Known issues (applicability)

• Ford 3-valve 2-piece plug breakage: Not applicable. The Cherokee’s engines do not use the problematic Ford modular V8/V10 two-piece design.
• GM 5.3 ionization-sensing coils: Not applicable.
• Cherokee-specific notes: Misfires are more commonly caused by worn plugs past their interval, oil in plug tubes from aging valve cover seals, or torn coil boots. On the 3.2L, ensure the intake manifold seals are renewed to prevent lean conditions after service. Always clear debris from plug wells before removal to avoid contamination of the cylinders.

Sticking with VIN-correct, fine-wire iridium plugs at the specified gap and torque will keep the 2.4L and 3.2L running smoothly for the full interval.

Need plugs replaced? Find a shop on Repairius.