Spark plugs: common defects and their signs

1. Lifetime end
   • The engine starts with troubles or doesn’t start at all.
   • The engine operation is not stable at idling.
   • Engine power output decreases.
   • Fuel consumption increased.
   • Foreign sound is heard during engine operation.
2. Soiling
   • The engine operation is not stable, the car moves jerkily.
   • The fact that the spark plugs are wet or covered with carbon deposits can be found during visual inspection.
   • Foreign sounds are heard during warming up or idling.
   • Fuel consumption significantly increased.
   • The engine revs up with difficulty, its power lowered.

How to repair or replace spark plugs?

If the spark plugs are broken down you should not try to repair them. They are to be replaced. Regularity of scheduled components replacement depends on electrode production material. For copper-nickel plugs it is 20,000 – 30,000 operational kilometers, while for the components with electrode made of noble materials (platinum, iridium, palladium, yttrium) – 60,000 – 100,000 km. Take into account that access to the spark plugs may be troubled, and a torque wrench should be used during installation of the components, also required tightening torque must be followed. That is why, if you don’t have such experience and special knowledge, it is better to entrust replacement of these spare parts to car station specialists.