Changing Spark Plugs




Changing Spark Plugs


Things You’ll Need

A 3/8 or 1/2 inch socket driver

Extension(s) 3 and/or 6 inches

Socket for your plug size (usually around 1/2 to 3/4in)

Swivel adapter for tight spaces

New spark plugs

A spark plug gapper


  1. Gather the necessary tools and replacement parts listed below, including the socket, driver, extension(s), new plugs, a gapper and some rags if the wires and/or engine is dirty or greasy.
  2. Make sure the engine has had time to cool off. The plugs will be hot for a little while after a running engine has been shut off.
  3. Remove the spark plug wire by pulling it in the same direction that the plug is pointing. The boot on the spark plug may be difficult to get off so pay attention to where your hand is going to go when it does come free. I say this from painful experience.
  4. After you ensure there is no dirt, oil or debris that can fall into the cylinder after you remove the plug, remove the plug by putting the socket wrench/driver on the plug and carefully turning it to the left, counter-clockwise. 
  5. Once the plug is free, pull it straight out being careful not to bang it into anything.
  6. Make sure the new plug is set to the correct gap using your gapping tool and data. You can get that particular plugs from the parts store where you buy it, either your local parts store or on-line.
  7. Install the new plug, being careful not to tap the tip on the engine block because it could easily change the gap setting causing the engine to run poorly. Do not over-tighten the spark plug. If you don't have torque spec's and a torque wrench I suggest you tighten it by hand as far as you can (with or without the socket on there (without the driver!), then use the driver/handle to tighten it another 1/8th of a turn.
  8. Re-connect the spark plug wire. Wiggle it and give it a light tug to make sure it seated properly. You should be able to feel it when it gets on correctly.
  9. If you have more than one cylinder, follow steps three through eight in their entirely for all the remaining plugs. It is best to do them one at a time so you don't risk putting them back in the wrong place, which would cause the engine to misfire or not start at all.



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    3 Discussions


    7 years ago on Introduction

    Remember also that, some engines have the spark plug wires in a so tight space that one can barelly stretch a pair of fingers and is unable to grab the plulg to remove it. An extractor tool is in practice a must have for this job. I´ve easily ruined one of my car engine wires by not pulling it off correctly. :-)


    7 years ago on Introduction

    You should put a squirt of wd-40 (or similar) on the threads of the new spark plug before insertion. Pry the spray nozzle off the can and lightly press the plastic tip into the threads. Prevents corrosion and makes future removal a breeze.


    7 years ago on Introduction

    Welcome to Instructables and congrats on publishing your first one! This looks like a seriously useful Instructable and I think it would be great as a "step by step" Instructable with photos accompanying each step of the process. If you have any questions about how to do that, I am happy to help.