Spark plugs are a crucial element in making your car engine run. When considering changing your spark plugs you need to take into account a couple of things:

  • The frequency at which you should change your spark plugs, which can be found in your Owners Manual
  • Where your spark plugs are located in your engine – some V6 engines require the removal of intake manifold(s)
What you'll need
Procedure

Step 1 – Mark and remove high tension lead/coil assembly

Refer to your manual to locate the spark plug high tension (HT) lead/coils.

 

Some vehicles do not have HT leads, instead they have an ignition coil per spark plug or per two spark plugs.

Mark each lead using tape to show the order in which they are connected. Crossed leads will cause the engine to run rough so it is crucial you get this step right.

Before removing any spark plug, remove the spark plug high tension lead by grasping the boot where it connects to the plug. Twist it and pull it firmly straight out.

Step 2 – Clean loose dirt away

If possible use a small paint brush to clean away any dirt or dust around the base of the plug, which may fall into the cylinder when the plug has been removed.

Step 3 – Select correct spark plug tool

The correct tool to use is a spark plug socket. This usually has a rubber insert to protect the plug while it is being removed.

Step 4 – Remove the spark plug

Spark plugs can sometimes be difficult to remove, so you may need an extension to gain additional leverage. Turn the spark plug counter clockwise to loosen it and then turn it by hand until removed. Remove the spark plug from the socket and clean it, brushing away any light deposits with a wire brush.

Step 5 – Clean the plug and check condition

Check the condition of the plug. If the insulator is cracked, the electrodes are burned or heavily corroded, or the thread is stripped, then the plug will need to be replaced. If the plug is dirty or oily this may indicate a problem elsewhere and you should get an expert to check it out.

Step 6 – Obtain a replacement plug

There are hundreds of types of different spark plugs and Supercheap Auto has most of them. So make sure the replacement you install has the correct code number for the type of vehicle you are servicing.

Step 7 – Check and adjust the gap

Check the plug specifications for the correct gap, and measure this with a wire gauge of the correct diameter. If the gap between the electrodes is too wide or too narrow, adjust it by bending the group electrode with a gap adjusting tool and slowly adjust the distance between the two electrodes.

Step 8 - Refit the spark plugs and torque to specifications

Apply anti-seize compound to the thread and replace the spark plug into the motor, carefully screwing it in by hand to avoid stripping the thread. When the plug is finger tight use a torque wrench to tighten the spark plug to correct specifications. Do not over tighten as this can damage the plug and the thread.

Step 9 – Replace the spark plug / lead coil assembly

Apply some silicon lubricant to the inside of the boot at the end of the coil leads and push it firmly into place over the exposed spark plug terminal. Reattach the spark plug coil leads to the same plugs they were attached to originally, and then remove the tape.

Step 10 – Start the engine

Close the bonnet and start the engine to confirm the plugs and leads are functioning properly and the engine is not misfiring.

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Please Read: Important Information