How To Change Spark Plugs
Learn how to change spark plugs. Replacing the spark plugs in your vehicle is an easy project when you know exactly what to do.
Replacing the spark plugs in your vehicle is an easy project when you know exactly what to do. Any car with an electronic ignition should have the spark plugs changed every 24,000 miles or 2 years, which ever comes first. If your car has breaker points the spark plugs should be changed every 12,000 miles or once a year.
Before you attempt to change your spark plugs you should check to be sure that there is at least two inches of clearance above them. If there is you can do the job yourself. Always make sure that your car engine is cool before starting this project and never try to change your spark plugs with the ignition turned on.
To begin you will need to tape identifying marks to each spark plug wire. This can be done by wrapping a piece of white masking tape around the wire and marking it with the wire's position. After all the wires are marked remove them and grasp each at the nipple end, twisting to break any heat seal. Then pull upward on the nipple end to remove the wire. Do not remove your wires by pulling on the wire itself since this can damage the wire. You will need a ratchet wrench to remove the plugs. In most cases a 13\16 or 5\8 inch spark plug socket will work with your wrench to remove the plugs. Of course the size you will need will depend on the size of your plugs. Since some of the plugs are in areas that are awkward to get at a universal joint drive handle attachment and extension attachments will make your project much easier.
To remove each plug, fit the socket firmly over the hex section of the plug and set your rachet to unlock. Using a counter clockwise motion apply pressure to the plug. If the plug will not turn, strike the handle of the ratchet with the heel of your hand to help unseat it. If this does not work use WD40 or another penetrating oil to spray the plug and wait 5 minutes before trying to remove it. Anytime you have a difficult time removing a plug you should clean the threads of the hole with a thread chaser prior to installing new plugs. Replace the plugs with the exact brand and model number that is recommended by the manufacturer of your car or the equivalent of what is recommended.
When your engine has an aluminum head you will need to apply a light film of anti-seize compound to the threads of each new spark plug. This can be purchased at any local auto parts store. To adjust the gap between the electrodes of each new plug you will need a spark plug gauge. The specifications you will need can be found on a decal under your cars hood or in your owners manual. In all cases, the gauge wire will need to fit firmly into the gap. Use the gauge's bracket to bend the L shaped side electrode and then recheck it with the wire. To reseat your plugs, thread each one into its original hole by hand tightening it as tight as possible. If your plugs have gaskets you will need to use your ratchet to tighten it a quarter to a half turn more. If your plugs do not have gaskets you will only need to tighten one sixteenth of a turn with your ratchet. Before replacing your cables, apply a light coat of silicone dielectric grease to the inside of each cable terminal and then push each terminal onto the nipple of the spark plug.