How to Replace a Spark Plug in a Car

Spark Plug Replacement

Back in the day, one of the simplest DIY tasks related to car repair is Spark Plug Replacement. However, these days, it has now gotten more complicated. Many of the newer cars have aluminum cylinder heads, coil on plug ignition systems, and very hard to reach spark plugs. However, this does not, mean that this job is no longer possible for you to change your own spark plugs. You just need more information to accomplish the job.

Can You Replace Your Spark Plugs Yourself?

Replacing your spark plugs is actually a fairly easy job most people can do themselves. Keep in mind there are some vehicles that have the spark plugs in very hard to reach places.

The good news is that most cars newer than 2000 have spark plugs that are fairly easy to reach. Be sure you read your service manual first before you start so you know what you are getting into. After you do that there are just a few things that are very important to remember.

How to Replace a Spark Plug in a Car

Finding a spark plug that fits your vehicle is simple. You can Google it by searching your vehicle’s year, make and model, or go to an auto store and look it up there.

  • Wait for Your Car Engine to Cool Down!

Skipping this step you might find it impossible to remove the spark plugs from your engine without ruining the threads. This is particularly true for aluminum cylinder heads. While it is possible to repair spark plugs that the threads are ruined, it is very difficult and should be left to a professional.

  • Blow-Out Debris around Spark Plugs

Blow off any dust, dirt or debris around the spark plug with an air duster. The last thing you’ll want is debris, and foreign particles falling STRAIGHT into your engine and certainly causing untimely engine wear.

  • Make Sure the Spark Plugs are turned in Straight.

You will have a problem if the spark plugs go in crooked, they can cross thread and cause damage. You can make sure your spark plugs are screwed in straight by wiggling them a bit as you are inserting them in. If you feel the spark plug getting tight in the beginning… you need to stop, take it out and start the screwing process over.

  • Change Spark Plugs One at a Time.

It’s quite easy to mix up the wires, play it safe and do them one at a time. If you have a car with a coil-on-plug system then you won’t have as much to worry about. Also, most all newer cars make it easy to put parts in the right places, but mainly older cars you have to be more careful with.

Tools Needed for Spark Plug Replacement

There are a few basic tools required in changing spark plugs. As mentioned above, use an air duster to blow off dirt and debris around the cylinders before you replace the spark plugs. You also need to have a spark plug gap tool, this is used to adjust the gap between the electrodes.

Make sure that you possess a spark plug socket. This socket has a rubber insert it will keep the spark plug from breaking while you are installing and removing the spark plugs.

If however you have a coil-on-plug system, you will most likely need either a screwdriver or a small socket wrench as most of them will be bolted on.


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