Tools You'll Need:
* Socket wrench set: You'll need a socket that fits your spark plugs (likely a 5/8" or 13mm). A ratchet and extensions will also be helpful.
* Spark plug socket: This socket has a rubber insert to grip the spark plug without damaging it. A magnetic spark plug socket is highly recommended to easily retrieve the plugs.
* Wrench for coil pack mounting bolts: This will vary depending on your specific Wrangler; check your manual for the size. Might be a 10mm or 8mm.
* Gloves: To protect your hands from grease and dirt.
* Safety glasses: To protect your eyes from flying debris.
* New spark plugs: Make sure you buy the correct type and gap for your engine. Consult your owner's manual or a parts store for the correct specifications.
* Torque wrench (recommended): This is crucial to avoid over-tightening or under-tightening the spark plugs, which can damage the engine.
* Penetrating oil (optional but helpful): If the plugs are difficult to remove.
* Shop rag or paper towels
Procedure:
1. Disconnect the battery: This is a crucial safety step to prevent accidental shorts or shocks. Disconnect the negative (-) terminal first.
2. Locate the spark plug wires/coil packs: On the 2.4L engine, the coil packs sit atop the spark plugs.
3. Remove the coil packs: Unscrew and remove the bolts holding each coil pack to the engine. Gently lift the coil pack off each spark plug. *Take note of which coil pack goes where if you're not already familiar.* Sometimes there are numbers cast into the valve cover to help.
4. Clean the area: Use compressed air or a shop rag to clean any debris away from the area around the spark plugs. This prevents dirt from falling into the cylinder.
5. Remove the old spark plugs: Use your spark plug socket and ratchet to carefully remove each spark plug. If a plug is particularly stubborn, apply penetrating oil and let it sit for a few minutes. Be careful not to drop the plug into the cylinder.
6. Install the new spark plugs: Carefully screw in the new spark plugs by hand until they are snug. Then, use your spark plug socket and ratchet to tighten them according to the manufacturer's torque specification (found in your owner's manual). Do not over-tighten! Use a torque wrench to ensure you get the right amount of tightening.
7. Reinstall the coil packs: Carefully place the coil packs back onto the spark plugs, ensuring they are properly seated. Tighten the mounting bolts to the manufacturer's torque specification.
8. Reconnect the battery: Reconnect the positive (+) terminal first, then the negative (-) terminal.
9. Start the engine: Check for any misfires or unusual noises. If everything is good, you've successfully changed your spark plugs.
Important Considerations:
* Gap: If your new plugs are not pre-gapped, you'll need a spark plug gapping tool to set the gap to the correct specification.
* Torque: Over-tightening the spark plugs can easily strip the threads in the engine block, leading to major engine damage. This is why a torque wrench is highly recommended.
* Difficulty: Accessing the spark plugs can be somewhat tight in the engine bay. A swivel socket or extension might be very useful.
If you are uncomfortable performing this task yourself, it's always best to take your Jeep to a qualified mechanic. The cost of repair versus potential engine damage makes this a sensible option if you lack experience.
