Thursday 19th February 2015
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Inspecting and changing spark plugs in your car on a regular basis is vital to make sure your car is well maintained and that the vehicles reliability of A to B journeys is at its peak. The average spark plug lasts about 10,000 to 20,000 miles.  YouTube has plenty of videos on changing spark plugs and there is a high chance that if you type in your make and model also, there will be a step to step process you can follow. Halfords have a great guide for helping drivers to change spark plugs.  Check it out here.

Here are some tips from

  • First check the coil pack which slots in on top of the plugs. The coil pack must be working correctly as it multiplies the spark plugs voltage which can be 50,000 to 75,000 Volts.  This is very important for the vehicle's combustion cycle. If the coil pack needs replacing it can be easily established as there will be an ash like substance in the coil pack.
  • Make sure you buy good quality spark plugs, preferably ones that  your vehicle's manufacturer recommends.  This will last a lot longer than cheap budget plugs. They will create a better spark whist also improving fuel economy and enhance the car's performance.
  • Wait for the engine to cool before inspecting and changing them, this will reduce the risk of getting burnt from hot plugs.
  • Check for wear and tear on the plugs. You can tell ifthe plugs need to be replaced if there is a dark ash like substance formed on the spark contact area.
  • You will need a ratchet., long extension and deep socket (usually 16mm but check with the manufacturer's specification)
  • Be careful that you don't cross thread the plugs. This can be avoided by using the extension and socket on the plug, winding it up hand tight.  It is important to tighten the plugs with a torque wrench to the setting the manufacturer recommends.
  • Best way to find the torque setting is to call your local dealership.

Look after your spark plugs

How to know when to change spark plugs

Here are some of the main indicators:

  • The engine will make a rough and jittery sound and produce larger vibrations when the car is idle in traffic.
  • The car is having trouble starting.  Most people assume this is because of the battery or lack of fuel but it could be because the spark plugs are poor quality or worn out. They may be unable to produce enough spark or could be making the battery drain. 
  • The engine misfires causing the car to stop very briefly, or the engine surges and you get a lot of stop and start movement aka 'engine hesitation'. 
  • Fuel economy deteriorates quite significantly and you have to fill up on petrol more often.  
  • Poor acceleration, hitting the accelerator feels different and less responsive. 

If you need spark plugs or any other parts visit right now.