Auto Repair For Dummies, 2nd Edition
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The first step in changing your spark plugs is to remove the old ones. To avoid turning this job into an all-weekend project, remove one spark plug at a time, inspect it, clean it, and — if it’s salvageable — gap the spark plugs. Then replace it before you move on to the next spark plug in cylinder sequence order.

To maintain the proper firing order, each spark-plug wire must go from the spark source to the proper spark plug. Therefore, only remove the wire from one plug at a time, and don’t disconnect both ends of the wire! This way, you won’t ever get into trouble — unless a second wire comes off accidentally.

Follow these steps to remove each spark plug:

Gently grasp a spark plug wire by the boot (the place where it connects to the spark plug), twist it, and pull it straight out.

Gently grasp a spark plug wire by the boot (the place where it connects to the spark plug), twist it, and pull it straight out.

Never yank on the wire itself (you can damage the wiring). The shiny thing sticking out of the engine block after you remove the wire from the spark plug is the terminal of the spark plug. This figure shows you all the parts of a spark plug, including the terminal.

Use a soft, clean rag or a small paint brush to clean the area where the spark plug enters the block.

You also can blow the dirt away with a soda straw. Cleaning the area keeps loose junk from falling down the hole into the cylinder when you remove the plug.

Place your spark plug socket (the big one with the rubber lining) over the spark plug; exert some pressure while turning it slightly to be sure that it’s all the way down.

Don’t be afraid to use some strength. But use it in a controlled manner. If you bang or jerk things, you can damage them.

Stick the square end of your ratchet handle into the square hole in the spark plug socket.

Adding a couple of extensions between the handle and the socket may help you move the handle freely from side to side without hitting anything.

Loosen the spark plug by turning it counterclockwise.

Loosen the spark plug by turning it counterclockwise.

To get the proper leverage, place your free hand over the head of the wrench, grasping the head firmly, and pull the handle, hitting it gently with the palm of your hand to get it going, as shown here.

Be sure your socket is securely over the plug and that the ratchet is at the same angle as the plug to avoid stripping the threads on the plug or in the spark plug hole in the engine head.

You may have some difficulty loosening a spark plug the first time. Grease, sludge, and other junk may have caused the plug to stick in place, especially if it’s been a long time since it was changed. If it feels stuck, try a little spray lubricant.

When the ratchet turns freely, finish the job by removing the ratchet handle and turning the socket by hand until the plug is free from the engine.

After you remove the spark plug from the engine, remove the plug from the socket. But don’t go on to the next plug until you’ve gapped and replaced it.

About This Article

This article is from the book:

About the book author:

Deanna Sclar is an acclaimed auto repair expert. She has appeared on hundreds of radio and TV shows, including NBC's Today show and the NBCNightly News. Sclar lectures internationally on the ecological impact of vehicles and is active in promoting residential solar energy programs. Sclar is also the author of Buying a Car For Dummies.

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