How to change your spark plugs

Spark plugs are probably one the most accurately names parts of your car, given their purpose is to channel the electrical current for the ignition, igniting the fuel. Therefore, it's not a stretch to say if these things blow, your car is going to be in a spot of bother. Thankfully though, they are relatively easy to replace when they've worn out, assuming your toolbox is up to scratch.


  1. Refer to your owner’s manual to locate your spark plugs. Don’t have your manual handy? Simply pop your bonnet, and look for the bundle of four to eight wires leading to different points on the engine compartment: the spark plugs are located at the engine end of these wires.
  2. Wait until your engine has cooled, then set about removing your current spark plugs. To do this, grip the wire plug as closely to the bottom as possible and set about working it off carefully to reveal the spark plug. Be gentle with it, as a damaged spark plug lead is just going to cause more headaches.
  3. Use your socket wrench fitted with an extension bar to remove the spark plug from its housing. Again, work slowly to avoid further issues.
  4. When the spark plug has been successfully removed, check the gap to determine if it needs replacing. Do make sure to only remove one plug at a time so as not to get them mixed up; spark plugs fire in a specific order, and crossing a wire to the wrong plug will effect the way your engine runs, maybe even damaging it.
  5. Now, how to ‘check the gap’, you ask? Refer to your owner’s manual (yeah, you really will need to keep that thing handy) to find out the optimum distance for your spark plug gap, and use a gap checker to measure the distance. If the distance of the spark plug gap is higher than it should be, you have two choices. You can either try and change the gap by gently tapping the plug on a wooden surface with the gauge in between the plug gap until you reach the desired measurement, or you can buy new plugs. The latter is probably the easiest of the two options, as they are not too expensive, and frankly, you should be changing your plugs every 20,000km or so anyway.
  6. Give your electrodes the once over to check for damage. You should expect them to be a little dirty, but if you see any white, limey build up around the electrodes of the plugs, or any signs of burning or parts of the electrode missing, you will most likely need to replace your plugs. Note, if the plugs are bent, black or broken, this may be a sign of a mechanical problem with your engine, and you should consult your mechanic as soon as possible.
  7. If it comes to it that you need to replace your plugs, the first step, obviously, is to purchase the correct replacement plugs. After this, you would be wise to clean up around the port before inserting the new plugs, using a wire brush or compressed air and replacing wires if necessary.
  8. Using your socket wrench again, insert the new plugs and tighten. Never over tighten your spark plugs as this can cause costly problems for your engine. Remember to replace the spark plug cables on the same plugs as they originally came from.
  9. And you’re done!