5.0L, 5.8L Windsor Spark Plug Replacement

How to Replace Spark Plugs in a 5.0L or 5.8L V-8 F-150

If you've replaced spark plugs before, changing them on a Ford Windsor V-8 (whether it's a 5.0L or 5.8L) is fairly straight forward and the engine bays on these vehicles have plenty of room to reach all 8 plugs without having to get creative. If this is your first time performing the task, take your time and follow the procedures below. Often times, the most difficult aspect of changing spark plugs is finding the correct tools to access confined spaces.

Cylinder #


Extension(s) Used


Passenger side, front (closest to radiator)

3" extension


Behind number 1, moving from front to rear

5" extension


Between cylinders 2 and 4

6" extension


Passenger side, rearmost (closest to firewall)

6" extension


Driver side, front (closest to radiator)

3" extension


Behind cylinder 5, moving from front rear

3" extension


Between cylinders 6 and 8

3" extension


Driver side, rearmost (closest to firewall)

No extension required


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Spark plug gap information sticker

• Disconnect the negative battery cable.

• The proper gap for the 5.8L Windsor in 1994 was .042"-.046". You can verify the required spark plug gap by finding the emissions label under the hood. On our subject vehicle, the emissions label was located on the inside of the hood, driver side.

Spark plug removal, passenger side

• The spark plug for a cylinder is located near the exhaust port for that cylinder. If you have difficulty finding one, simply trace the spark plug wires.

Spark plug removal, driver side

• Replace spark plugs and plug wires one at a time. Do not remove all the spark plug wires at once. By replacing them one at a time, you do not have to worry about crossed plug wires, which can result in an expensive repair bill.

Spark plug closeup in cylinder head

• Remove the spark plug wire from the spark plug. If the spark plug boot is deteriorating, do not worry, this is why we change spark plugs and plug wires at the same time (years of extreme heat will take its toll on the silicon boots). Sometimes the boots need a good wiggle to get them off, or you can use a spark plug boot removal tool to make it easy on yourself.

• With the boot removed, use a 5/8" spark plug socket to remove the spark plug. You may or may not need an extension to reach the spark plug. Refer to the list above to see what extension(s) worked to remove the spark plug for a corresponding cylinder.

Spark plug removed from cylinder head

• Be aware that the spark plugs are mounted at an angle into the engine block - you'll need to match this angle when installing the new ones, as you won't want to damage any of the threads.

Coating new spark plug in anti-sieze

• After removing the old spark plug, check the gap of your replacement plug and coat the threads of your new spark plug with anti seize compound.

• Install your new spark plug. Always hand start to thread the spark plug to ensure cross threading does not occur. Spark plugs get "snugged" up, do not overtighten.

• Apply a small amount of dielectric grease to the terminals of your new spark plug wire. Remove the old spark plug wire completely, then install the new wire, ensuring that the terminals are installed securely at both the tip of the spark plug and the distributor.