Tools You'll Need:
* Socket wrench set: You'll need a socket that fits the spark plug (likely 5/8" or 13mm), an extension, and a universal joint (highly recommended for easier access).
* Spark plug socket: This is a special socket designed to grip the spark plug without damaging it. It usually has a rubber insert.
* Wrench for spark plug wires (if applicable): Some Aerostars had clip-on spark plug wires, others may have used a bolt-on system. You might need pliers or a small wrench.
* New spark plugs: Make sure you purchase the correct type and heat range for your Aerostar's engine. Check your owner's manual or auto parts store for the right ones.
* Gloves: To protect your hands.
* Penetrating oil (optional): If the plugs are particularly stubborn.
* Rags or shop towels: To clean up any oil or dirt.
* Torque wrench (highly recommended): Overtightening spark plugs can damage the engine. A torque wrench ensures you tighten them to the manufacturer's specifications.
Procedure:
1. Safety First: Disconnect the negative (-) battery cable to prevent accidental shorts or sparks.
2. Locate Spark Plugs: The spark plugs are located on top of the engine. You'll need to locate the valve cover(s) and access the plugs from above. It can be somewhat cramped.
3. Remove Spark Plug Wires: Carefully disconnect the spark plug wires one at a time. If they are clamped on, gently pull them straight off. If bolted on, use the correct size wrench to remove them. Keep track of which wire goes to which plug. You can label them if needed.
4. Remove Spark Plugs: Use the spark plug socket and your wrench to carefully remove each spark plug. Spray penetrating oil if needed (allow it to sit for a while). Turn the socket counter-clockwise to loosen and remove the plug. Be careful not to drop the plugs into the engine.
5. Inspect Old Spark Plugs: Examine the old plugs for wear and tear. This can provide clues about potential engine issues.
6. Install New Spark Plugs: Before installing the new spark plugs, clean the spark plug well. Screw the new plugs in by hand until they are snug. Then, using the spark plug socket and wrench, tighten them to the manufacturer's specified torque. Do not overtighten. Use a torque wrench to ensure proper tightening.
7. Reconnect Spark Plug Wires: Carefully reconnect the spark plug wires, making sure each wire goes back to its original location.
8. Reconnect Battery Cable: Reconnect the negative (-) battery cable.
9. Start the Engine: Start the engine and listen for any unusual sounds.
Important Considerations:
* Access: Working in the engine bay of an Aerostar can be tight. You might need to use extensions and a universal joint to reach all the plugs.
* Torque: Using a torque wrench is crucial to prevent damaging the engine threads. Over-tightening is a common mistake.
* Heat Range: Use the correct heat range spark plugs for your engine. Using the wrong heat range can damage your engine.
If you are not comfortable performing this task yourself, it's best to take your Aerostar to a qualified mechanic. Improperly installed spark plugs can cause serious engine damage.
