Here's a general outline. Always consult your owner's manual for specific instructions and torque specifications. Failure to follow proper torque can damage the engine.
Tools You'll Need:
* Socket wrench set: You'll need a socket that fits your spark plugs (likely 5/8" or 13/16", check your owner's manual). A ratchet and extensions will also be helpful to reach all the plugs.
* Spark plug socket: A deep well spark plug socket is crucial to avoid damaging the plugs. It should have a rubber insert to grip the plug securely.
* Torque wrench: Absolutely essential to tighten the plugs to the correct specification. Over-tightening can strip the threads, while under-tightening can cause misfires.
* Gloves: Protect your hands.
* Safety glasses: Protect your eyes from potential debris.
* Shop rags or paper towels: To clean up any spilled oil or dirt.
* Penetrating oil (like PB Blaster): May help loosen stubborn plugs.
* New spark plugs: Use the correct type and heat range specified in your owner's manual.
Procedure:
1. Disconnect the negative battery cable: This is a crucial safety precaution to prevent accidental shorts.
2. Locate the spark plugs: On a 3.5L Chrysler 300, the spark plugs are typically located on top of the engine, accessible after removing some components. Refer to your owner's manual for the exact location and any specific access instructions. You might need to remove parts like the intake manifold or air intake system to access some plugs. This is where a repair manual becomes extremely helpful.
3. Remove the coil packs: The coil packs sit on top of the spark plugs. You'll need to carefully unclip or unbolt them (consult your owner's manual). Take note of the order they are removed so you can reinstall them correctly.
4. Remove the spark plugs: Spray penetrating oil onto the plug threads if they seem stuck. Use your spark plug socket and carefully remove each plug, turning it counterclockwise. Be gentle, as a stripped plug is a major headache.
5. Clean the spark plug wells: Use compressed air or a shop rag to remove any dirt or debris from the well.
6. Install the new spark plugs: Carefully install the new spark plugs by hand, screwing them in until they are snug. Do not overtighten by hand.
7. Tighten the spark plugs with a torque wrench: Use your torque wrench to tighten each plug to the manufacturer's specified torque. This is critical to avoid damaging the engine. The torque specification will be in your owner's manual.
8. Reinstall the coil packs: Carefully reattach the coil packs in the correct order.
9. Reconnect the negative battery cable.
10. Start the engine: Listen for any unusual noises or misfires.
Important Considerations:
* Repair Manual: Highly recommended. A repair manual specific to your 2004 Chrysler 300 3.5L will provide detailed diagrams and instructions, making the process much easier and safer.
* Gap: Some spark plugs require a specific gap. Check your owner's manual or the packaging of the new plugs. You'll need a spark plug gapping tool if adjustment is needed.
* Difficulty: Accessing some of the spark plugs can be challenging due to limited space in the engine bay. Be patient and methodical.
This is a simplified explanation. Improperly performing this task can cause significant engine damage. If you're not comfortable with automotive repair, take your vehicle to a qualified mechanic. It's much cheaper to pay for professional service than to repair engine damage resulting from incorrectly installed spark plugs.
