Not every auto repair requires a certified mechanic or auto repair shop.  When the time comes to change your spark plugs, it doesn’t have to mean a trip to the auto repair shop.  Changing your spark plugs is a pretty simple, basic maintenance job that will result in a smoother ride with better gas mileage.  This is a job that can easily be done by a confident home mechanic if you follow these directions.  Auto repair requires precision, so following the instructions exactly is very important.

Today’s auto repair job: Changing Spark Plugs

The spark plug is a high voltage bridge for electricity within the motor.  The bridge is really made as electricity crosses the gap between two contact points, allowing the spark to ignite the gas vapors within the motor, allowing the engine to run.  Spark plugs are a relatively inexpensive auto part and both easy and quick to change.  It is very important that you follow the instructions, as failure to do so could definitely complicate the job.

Items You Will Need

You should always gather the tools and supplies you will need before you get started on an auto repair. This will ensure that you actually have all of the tools you may need, including any specialty tools required for specific jobs, as well as simplifying the entire task by just having everything in order and within reach.  For changing your spark plug you will want to gather your ratchet wrench, a spark plug socket for your particular type, a 12-inch socket extension, and, of course, the new spark plugs to be installed.

Find the Spark Plugs

Locating spark plugs is easy: simply trace the thick, rubber spark plug wires back to the ends where the actual spark plugs are attached on each end of each wire.  The spark plugs are located in different places based on your engine type.  On a 4-cylinder engine, you will find 4 spark plugs that should be situated at the top of the engine.  They will be in a row.  In a V8, there will be more of a reach.  One both sides of the engine you will reach down and find 4 spark plugs, totaling 8 plugs in all.  In a 6-cylinder engine, it could actually be either way.  Just follow the plug wires and you’ll get there.

Removing the Spark Plug Wires

Before you touch ANYTHING you need to be aware that this step needs to be done in a particular order.  This is very important.  The first wire you should take out should be from the end of the line.  When you remove the spark plug wire you want to use caution.  Pulling on the wire too hard can and WILL damage them, pulling the wire from the boot.  You should grasp it as close to the engine as you can and pull it gently, although you may have to wiggle a little to loosen it.  In 4-cylinder engines with a dual over head cam top end configuration, the spark plug wires go into holes on top.  In this instance you will simply pull the wire straight up to pull the rubber boot from the hole.

How to Remove the Spark Plugs

Now that you have the first wire off, you will need the tools you gathered earlier.   Get the spark plug socket and extension onto your ratchet.  Inside the spark plug socket you will see a black colored foam or rubber.  This is what grips and holds your spark plug while you are removing it from the engine.  With your ratchet set to counter-clockwise you will slide it over the end of your spark plug.  Press it onto it as far as it will go and remove the old spark plug.

Inspecting the Spark Plugs and Spark Plug Wire Ends

Have a good look at the worn plug you removed.  How does it look?  There should be some dirt on the end with a small amount of soot.  That mentioned, it should only be a small amount of soot and if it is oily or white in color you may be looking at other auto problems.  You should also take a look at the porcelain insulator to check for cracks.  You also need to inspect the end of the plug wire.  Some are simply threaded like a screw would be, while others have a metal cap.  Make sure that the new plugs are set up exactly like the ones you are removing.

Installing a New Spark Plug

Since we now order spark plugs made specifically for the car we’re working on, there is no longer a need for a gapping tool.  The new plugs should already be gapped when you get them.

In With the New Plug

With the wire end of your plug set up like the old one, you’re ready to put it in the car.  Place the plug-wire end of your spark plug into the socket.  Holding only the extension you will push the new spark plug all the way in, guiding it into the hole.  Handling the plug roughly can damage the plug or mess up the gap.  Install the new plug with caution and care.  Once it is sitting in the hole correctly, you should screw it in by hand.  It is better to do this by hand since starting with the wrench could cause you to accidentally cross-thread a plug.  Only use the wrench to tighten down once you’ve screwed it in by hand as tightly as possible.  If you’re using a torque wrench, you can torque to the specifications.  If not, just tighten down until it fits in snug and tight, but not too far or forcing anything too far.  Because the metal is soft, over tightening it may cause damage.

You should now inspect the spark plug wires themselves.  If they are worn or damaged you should replace them at this point.  Now it is time to plug the wire back on.

Now For the Rest

You’ve successfully changed your first spark plug.  You will now repeat this entire procedure for each plug, one plug at a time.  Once they have all been changed, start the vehicle and listen to your handiwork!  You are finished and back on the road with a smooth ride and much better gas mileage when you started this auto repair adventure.  Congratulations, you’ve done good work!