Spark plugs

Without spark plugs a petrol engine cannot function. They have been an integral part and the basis for engine propulsion for around 120 years. At the same time, they are a typical wearing part in the vehicle, especially if the car is frequently exposed to damp and cold weather. If they need to be replaced, ORIGINAL spark plugs are the best choice because they have a long service life. With us you find the ORIGINAL spark plugs of the vehicle manufacturers at very favourable prices. At the bottom of the page you can learn more about how the spark plugs work and what to consider when buying and changing them.

The function of the spark plugs

Spark plugs ignite the mixture of air and gasoline prepared by the injection system or carburetor with a spark in the compression tract. After ignition, this spark generates a constant explosion pressure that pushes the piston downwards. This sets the crankshaft in motion, which drives the engine. The ignition spark jumps over between the middle and ground electrode. The optimum electrode distance depends on the engine and is specified by the vehicle manufacturer or the engine manufacturer.

Each cylinder has at least one spark plug. In rare cases two are needed per cylinder. As they are wearing parts, they should be replaced approx. every 30,000 km - 60,000 km. This is generally done during the regular maintenance intervals, even if the number of kilometres has not yet been reached. You will find more information in your service booklet. However, modern spark plugs with iridium or platinum electrodes can also achieve a service life of up to 100,000 km. These materials have better heat resistance.

What happens when spark plugs break and how do I recognize this?

Defective spark plugs can be avoided by observing the maintenance intervals. There are no misfires during acceleration and engine damage is also avoided. When changing the spark plugs, also ensure that the spark plugs are replaced correctly. Incorrect spark plugs can cause the same effects. It is therefore advisable to use ORIGINAL spark plugs.

Symptoms of defective spark plugs can be:

• High fuel consumption with low engine power
• A cumbersome engine start
• A sudden stop of the engine when it is in neutral
• Uneven engine running

Defective spark plugs can be identified by blackened and worn electrodes, heavy deposits on the plug, fusion (white discoloration), sooting or oiling. The above-mentioned symptoms are mainly favoured by short distances, as the spark plugs can only be released at a certain temperature.

What should be observed when buying and changing spark plugs?

Basically, the same type of spark plugs should be purchased that have previously provided sparks in the vehicle without any problems. The required spark plug is often mentioned in the vehicle manual. The most important criteria such as thread length, heat value and electrode distance should match. Most important is the heat value, because an incorrect heat value can lead to dropouts or damage.

Basically the change is easy. However, spark plugs should only be changed by a professional in a specialist workshop! Because many mistakes can happen during this process, for example:

• Make sure that no dirt gets into the combustion chamber when removing the old candle.
• The spark plug connectors should be visually checked for damage.
• Spark plugs that have fallen down must not be used again.
• They must be used with a spark plug wrench. A torque wrench ensures that it is not screwed in too tightly and not too loosely.

Above all, when inserting it, it must be taken into account that the material expands under the effect of heat. For this reason, there must be enough leeway. Here the correct tightening torque in Newton metres (Nm) is important! If the spark plug is too tight, the cylinder head can be damaged. If the spark plug is too loose, the heat cannot be dissipated properly, so that the combustion chamber may leak.

Is it enough to even clean a spark plug or does it always have to be replaced?

If the spark plugs are only dirty, they can only be cleaned first. However, the same things have to be observed here as when changing spark plugs. When cleaning, you should first wipe them with a cloth and then clean the electrode with the wire brush. Again, it is important to note that the spark plugs must be screwed back into the cylinder head with a certain torque. If the problems have not improved, they must be replaced.

Spark plugs are generally inexpensive and changing spark plugs is not a major expense. It is therefore worthwhile to change them regularly, and thus to avoid defects and failure symptoms! Find out exactly which ORIGINAL spark plugs are required for your vehicle before you buy and have them changed in a specialist workshop.

We would be happy to help you find the right spark plugs. You can already limit the spark plugs that come into question by means of the vehicle selection. Please note the restrictions described in the red fields - the right spark plug will be found quickly. If you are still unsure, please contact our customer service