How to Check Spark Plugs in a Car

April 9th, 2020 by

One of the most important aspects of your car’s engine is its spark plugs. These small electrodes give the engine the power needed to make your engine run and move your car down the road. But, they need to be changed out from time to time. So how do we know when this needs to occur? Here is a quick how-to guide to check your spark plugs.

Safety Brief

Safety Brief!

Spark plugs are a main part of your engine and provide its ability to function. DO NOT run your engine while checking your spark plugs as it will not only cause damage to the engine, but could also harm you in the process. If your engine was running, let it cool down before doing this as both the engine and spark plugs get extremely hot.

Now, let’s get started.


Socket Wrench, Socket, and Extender

  • Get a socket wrench and a socket that fits the spark plugs (there are special sockets meant to accomplish this task that have padding in them to protect the porcelain part of the spark plug). You can also use a socket wrench extender, if you happen to have one, as it will make removal easier.
  • Check to make sure the car is fully shutdown and not running in any capacity. Remove the keys from the ignition. Keep in mind again if the car has been running, wait for the engine to cool down.
  • Clear the area around the spark plugs of any debris or dirt. Using an air compressor for this will work best. That will ensure that no debris will fall into the cylinder when the spark plug is removed.
  • Remove the spark plug wire from the spark plug you are going to check.

Spark Plug Wire

Spark Plug Wire

  • Place the socket over the spark plug and begin to loosen it, once loosen unscrew the rest by hand and take out of the engine.
  • Examine for any cracks to the porcelain, damage to the threading and any burns to the electrode, do not worry about the electrode being a little dirty as you can clean that with a rag or wire brush to help you get a better look at the actual part.

Stuff to Check

  • Return the spark plug back to it’s cylinder if you find nothing wrong and screw back in by hand then tighten with the wrench to a snug fit and put the spark plug wire back on.
  • Repeat this for the rest of your engine’s spark plugs.

Now, if any of your spark plugs are damaged they can be easily replaced by looking at your owner’s manual and finding what spark plugs are the best for your car as well as the gapping that is needed for the electrode.

You may want to seek out your mechanic, if you do not know what you are doing, so they can do the work properly as well as make sure there is nothing else wrong with your car’s engine caused by the bad spark plugs. This will help avoid any unnecessary damage to the engine or having to replace your spark plugs again.

For reference, you would want to replace them every 80,000 miles as they are mostly worn by this point.

To find a Basil Family Dealerships’ service center near you, click here.

Posted in Service