The spark plug is an essential component of the ignition system of a gasoline engine. It is located at the heart of each cylinder and delivers the spark that triggers the combustion of the air-fuel mixture. It consists of an upper part, connected by the high voltage wire to the coil. The other part, called the base, is screwed into the breech and contains the electrode that generates the spark. The quality of the spark provided by the spark plug determines the combustion force and therefore the power and flexibility of your engine.

Why change your spark plugs?

A faulty candle causes the following symptoms:
  • Engine that lacks power
  • Excess fuel consumption
  • Engine that pollutes, then pay attention to the health of the catalyst.

When to change spark plugs?

Spark plugs are replaced at intervals that can vary from 30,000 km to 60,000 km depending on the manufacturer's recommendations (see vehicle maintenance manual). It is necessary to replace all spark plugs, even if only one spark plug is defective, in order to avoid an unbalanced ignition. On some models there are two candles per cylinder that can be replaced in pairs. They are identical or different depending on the engine.

How to change spark plugs?

Removal of spark plugs

Disconnect the negative terminal from the battery, as specified in the Safety Instructions. It is imperative to let the vehicle cool down to remove a spark plug. Clear access to the spark plugs depending on the version: cover, intake manifold, air filter housing etc.

Installation of spark plugs

Before installing the new spark plugs, make sure that the new spark plug is identical to the one removed. Check the tightness of the connection piece or remove it depending on the type of connection. Check the electrode gap and ensure that the porcelain part is not broken or cracked. The spacing of the same spark plug varies according to the engine of the vehicle (see vehicle technical review or spark plug packaging). By default, the spark plugs are set to a maximum spacing, so it may sometimes have to be tightened again.

Pre-clean the spark plug reception opening with a blowgun

Install the new spark plug in its housing by hand using the spark plug wrench extension, making sure it is straight. An improperly mounted spark plug can damage the cylinder head thread. Finish tightening moderately with the spark plug wrench. Reassemble the coil or the ignition wire directly to the corresponding cylinder, as the case may be.