How to tell when spark plugs are failing and when to replace them

It cannot be said that one engine component is more important than another, since in reality all of them are necessary for the car to run properly. But we can tell you how to find out whether any of those parts is malfunctioning and needs replacing. The signs may be very subtle at first and we may not be aware that something is wrong, but you must stay alert, because a fault caught in time can be a real saving, since it can get worse and then become a genuine problem.

Spark plugs are the device that creates the spark that ignites the fuel and causes the explosion that makes the car move. Like everything else, they wear out with use and start giving signals that can be observed and help prevent a fault that is difficult to repair and, above all, expensive. One of the first signs of a problem with the spark plugs can be a misfire. Poor spark plug ignition can cause a characteristic sound. A misfire does not necessarily mean that the spark plug is faulty, but if it occurs constantly, it is a clear sign that you should visit the workshop.

Another indication, possibly the most important and one that can pose an immediate risk, is a loss of engine power. This can be especially noticeable on hills, so it is easy to detect and requires an urgent visit to the workshop. The main reason spark plugs fail is use. They are a component that operates continuously and suffers considerable wear. Spark plugs are designed to last, but inevitably the time comes to replace them before they cause serious damage.

The wear of the electrode, the part of the spark plug that produces the spark, is the most common problem, but the porcelain insulator can also crack. The presence of oil in the cylinders can also cause the spark plugs to become dirty and work inefficiently, as can soot forming at the moment of combustion.

As with all engine components, spark plug replacement can be carried out at home, if you have the skill and knowledge to do it safely. A spark plug socket is required, with the exact diameter to carry out the job efficiently and without damaging anything. Even so, the ever-greater complexity of engines means it is advisable to visit the workshop when this job needs doing. It is much safer and quicker, and it is not an expensive operation, so it is better to have a professional do it, with every guarantee.