How to change spark plugs in car engine – tips and precautions

Modern cars usually have spark plugs that have a significantly longer lifespan than previous models. You still have to change them sometime. With the right tool, it’s not that difficult.

Spark plugs need to be changed regularly

Many components of a car are wearing parts. This also includes the spark plugs.


Older spark plugs should be replaced after about 10,000 km. Today only long life candles are usually used. These have a significantly longer lifespan. A change is only due after 30,000 to 60,000 km.

Signs of used spark plugs are starting problem, misfiring and jerking while driving. However, reduced engine output and increased fuel consumption also indicate that it is time for spare parts.

The safest indication is the visual inspection. If the electrodes look burned or charred, they are used up.

You can find out which spark plugs you need for your vehicle in the operating instructions. If you do not have them at hand, ask your specialist dealer for the right spare part for your vehicle model.

How to remove the spark plugs

Changing the spark plugs is not difficult with the right tools. You definitely need a spark plug wrench , a torque wrench is an advantage. However, the engine must cool down before you get to work.

Open the hood, you will see the engine block. The ignition cables are usually located on the side and lead from the distributor to the engine block or to the cylinder head. In modern engines, there is usually a plastic cover over the engine. You must remove this first. The number of ignition cables corresponds to the number of cylinders in your engine. So if you have a 4-cylinder engine, you need four new spark plugs.


To get to the actual spark plug, you must first remove the spark plug connector. This can take a little bit of strength.

Now you can see the upper part of the old spark plug. Insert the spark plug wrench here and turn it to the left.

Installing new spark plug

If the old spark plug is removed, you can install the spare part. It is important to use the correct tightening value. If the ignition short is too loose, it will not work properly. If it is turned too tight, it will be damaged. We explain how this works with and without a torque wrench.

Insert the new spark plug and turn it to the right. We recommend a torque wrench for tightening. You can find out the correct tightening value from the spark plug manufacturer or from specialist retailers.

If you don’t have a torque wrench at hand, you can do it without one. However, you should then observe the following rule of thumb in order not to damage the spark plug: If the new spark plug has a sealing ring, it is tightened by 90 degrees clockwise, i.e. a quarter turn. Spark plugs without a sealing ring are tightened by 15 degrees. This corresponds to about two minutes on a clock face.

Finally, all you have to do is plug in the spark plug cable.

Close the hood and start the car. You can tell whether the spark plug change was successful from the fact that the car starts up on the first try. In addition, the engine should run smoothly.

Contact the author: denzilrey@wheelsjoint.com



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