How to Change Your Spark Plugs

In your car, the spark plugs play an essential role. As the engine turns, the spark from the spark plug ignites the gas in the engine, turning the pistons. A malfunctioning or dirty spark plug can dramatically reduce performance and even cause damage to the engine, so it is important to regularly inspect and replace your spark plugs.

The condition of your spark plugs can tell you a great deal about your engine as well. For example, if the spark plug is covered in oil, this means you have a leaky seal. A spark plug that looks like it has blisters and is very white can be an indication that the spark plug is getting too hot. If the spark plug is melted, it can be a sign that the engine is igniting too early or that the engine is getting too hot.

Before removing your spark-plugs, make sure that you buy some new ones at the auto-parts store. There are many to choose from and one popular type are ones that have multiple spark points, often up to four points. I prefer the single or at most double spark points, as they work well and anything else is very pricy and not really needed for a regular car.

Make sure you ask if you need to “gap the spark plug" or if they are pre-gapped. The gap is simply the distance between the electrode and spark plug, which is easy to adjust with a inexpensive spark plug gapper. However, an improperly gapped spark plug can cause a number of engine problems. Most sparkplugs are pre-gapped.

When purchasing spark plugs, it is a good idea to find out what the manufacturer suggest. For instance, Ford uses Motor Craft Spark Plugs and Toyota's usually use NGK Spark Plugs, so going with the manufacturers recommended brand is a good idea.

You will also need a special socket to remove the spark plug, as well as possibly a long extension for your ratchet. The special spark plug socket has a piece of rubber in the top of it, which grabs the spark plug so that you can pull it out of the engine. Some vehicles, especially vans, can be quite tricky to get to and a flex joint can help make it easier to get the right amount of leverage in a small spot.

The auto-parts store will almost always try to up-sell you on a special type of grease, used to prevent the spark plug from sticking. This is rarely necessary, but it is part of their closing script, so they ask everyone.

Removing and Replacing the Spark Plugs

Since the order of the spark plug wires is essential, it is a good idea to change your spark plugs one at a time. This way, you do not risk putting the wrong wire on a spark plug. It is also a good idea to wait until the engine is completely cool, as the spark plugs and engine block can become very hot, even after only driving for a short period of time.

First, remove the spark plug wire by carefully grasping it with your hand or a pair of needle nose pliers. Wiggle the wire back and forth while lifting upwards and it should pop right off. You want to be careful, however, because it is easy to damage the wire when pulling it off.

Most wires come with a lifetime warranty, although this has become more limited over the last few years. So, make sure you use your real name and phone number when buying them, so that you can take them back if necessary.

Once the wire is removed, place it out of the way and remove the spark plug with the special spark plug socket. It is a good idea to put the socket on an extension and holding the end of the extension, put the socket onto the spark plug. Keep in mind that because of the rubber on in the spark plug socket, it may feel like it is on or be a little tougher to put on than a regular socket. Loosen the spark plug and once it is completely loose, you should be able to simply pull it out.

Visually inspect the spark plug and if it is damaged, keep track of which cylinder you pulled it out of.

When replacing the spark plug, insert it on the spark plug socket and insert into into the cylinder. Even though the rubber of the spark plug socket works well to hold the spark plug, be careful not to let it drop on the floor, which can damage the spark plug.

Also, be careful not to over tighten the spark plug, as it does not need to be too much more than hand tight. If you are at all unsure of how tight it should be, use a torque wrench and tighten the spark plugs to the manufacturers recommendation, which the auto parts store will be able to tell you and is also likely in your vehicles manual.

Once the spark plug is in place, carefully replace the spark plug wire with your hand, ensuring that it is firmly seated on the spark plug. You also want to make sure that the seal around the spark plug cylinder is tight and that the wire is correctly seated around the seal.

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