Spark Plug Replacement — JL Wrangler 3.6L Pentastar and 2.0T

# Spark Plug Replacement — JL Wrangler 3.6L Pentastar and 2.0T

Jeep recommends 30,000-mile spark plug intervals on the 3.6L Pentastar. The 2.0T eTorque is rated to 60,000 miles on its iridium plugs. Real-world experience in the Jeep community suggests the 30,000-mile interval holds up — the Pentastar is sensitive to worn plugs in a way the 2.0T is less so.

Both engines are accessible with standard tools. The 3.6L's plugs are split across both valve covers — three per side, accessed from above. The 2.0T has four in a row across the top of the engine and is slightly more accessible.

3.6L Pentastar:

• NGK Iridium IX BKR6EIX-11 (OEM spec) — 6 plugs
• 5/8" spark plug socket with rubber insert (18mm)
• 3" and 6" extensions
• Torque wrench (set to 13 ft-lb / 156 in-lb)
• Dielectric grease (apply to boot only, not threads)
• Compressed air or vacuum for debris in plug wells

2.0T Turbo:

• NGK Laser Iridium ILFR6B-11 (OEM spec) — 4 plugs
• 5/8" spark plug socket
• Torque wrench (set to 20 ft-lb)
• Same toolset as above

3.6L (both banks, same process)

1. Let the engine cool completely. Remove the engine cover (if equipped) by pulling straight up — it clips on.
2. Disconnect the ignition coil connector on each cylinder before removing the coil. The coil is held by a single 10mm bolt.
3. Remove the coil. Blow or vacuum any debris out of the plug well before breaking the plug loose — debris in the combustion chamber is a bad day.
4. Use the plug socket with an extension to loosen the plug — counterclockwise. It will be 18–20mm deep in the well.
5. Remove the old plug. Inspect: the electrode gap should be 0.044" new; worn plugs will show a wider gap, rounded electrode, or carbon deposits.
6. Check the new plug gap (pre-gapped from NGK but verify): 0.044" for the Pentastar.
7. Thread the new plug in by hand until snug — use a rubber hose on the plug body to avoid cross-threading. Torque to 13 ft-lb.
8. Reinstall the coil and torque the coil bolt to 89 in-lb (a little under 8 ft-lb).
9. Reconnect the coil connector — it will click.
10. Repeat for remaining 5 cylinders.

2.0T (4 plugs in a row)

1. Same prep: engine cool, remove coils (10mm bolts), clean plug wells.
2. Plug gap for the 2.0T: 0.028" — verify each plug before install.
3. Torque to 20 ft-lb (higher than the Pentastar — the 2.0T's aluminum head spec is different).
4. Reinstall coils to 89 in-lb.

• Cross-threading: The JL's aluminum heads do not forgive cross-threaded plugs. Thread by hand first. If you feel resistance before the plug is fully seated, back out and try again.
• Anti-seize on the threads: Mopar does not spec anti-seize on these plugs. NGK iridium plugs ship with a zinc coating that acts similarly. Do not add anti-seize — it changes the torque-tension relationship and can lead to overtorquing.
• Dielectric grease goes on the boot only: A small amount on the inside of the coil boot prevents it from seizing to the plug. Do not put it on the plug threads or electrode.
• Debris in the wells: Dirt in a combustion chamber causes scoring. Blow out the wells before loosening any plug. This step matters more on a dusty off-road rig than a clean street car.
• Misfires after the swap: Clear any stored codes with an OBD2 scanner after the job. New plugs on a high-mileage engine sometimes trigger a misfire initially — let it run a full heat cycle before diagnosing further.

• NGK ILFR6B-11 (2.0T, 4-pack): $35–$50
• Mopar OEM plugs from the dealer: $10–$14 each (same NGK spec with Mopar branding)
• Dielectric grease (tube): $5–$8

Labor at a shop runs $150–$250 depending on location. This is a straightforward DIY with a torque wrench — the only part that slows most people down is the rear bank plugs on the 3.6L, which require a 6" extension and some patience.

Tools required

• 5/8" spark plug socket
• torque wrench
• extension set
• ratchet
• compressed air or vacuum

Related

• All Jeep Wrangler JL guides & tools
• Browse the full DIY database

Written and maintained by an AZ wheeler and driveway wrencher. How we source guides. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.