How to Change Spark Plugs

The humble spark plug has changed very little over the years—and changing them is as simple as ever.

To complete this How-To you will need:

A vehicle owner's manual
New spark plugs
A socket wrench
A spark plug socket
A socket wrench swivel joint
And a socket wrench extension
A spark plug wire puller
A cleaning rag
And rubbing alcohol

Step 1: Let car cool down

Park your car and wait for it to cool down. This may take a few hours, since the spark plugs are among the hottest parts of your engine.

Step 2: Locate spark plugs

Pop open the hood and locate your spark plugs by referring to your owner's manual.

Step 3: Remove one spark plug

Remove one spark plug wire from the end of the row by pulling its boot, or the little cap where it connects to the engine—not by yanking on the wire itself.

Tip: You can also use a spark plug wire puller to easily detach the wire.

Step 4: Attach spark plug to socket wrench

Attach the spark plug socket to the socket wrench. You may need to use a swivel joint and/or a socket wrench extension to reach the spark plug.

Step 5: Remove spark plug

Remove the spark plug by turning the socket wrench counterclockwise.

Step 6: Make sure hole's clean

Make sure that the spark plug hole is clean. If necessary, use a rag and rubbing alcohol or compressed air to clean the spark plug hole.

Step 7: Install new spark plug

Carefully install a new spark plug into the empty hole and tighten it by hand.

Step 8: Secure new spark plug

Use the socket wrench to secure the new spark plug in place.

Step 9: Reconnect spark plug wire

Reconnect the spark plug wire onto the new spark plug.

Tip: Changing your spark plugs one at a time prevents incorrect installation that can affect the car's timing and engine performance.

Step 10: Move on to next spark plug

When you have successfully changed a spark plug, move on to the next one until you have finished installing all new plugs.