The spark plugs are responsible for blowing up a bow positive coil current traveling by means of an electrode isolated by ceramic with negative mass, which goes in the body of the plug. The spark plugs differ by size, thread and thermal range, and also have the ability to cool in their workplace. It should always wear those recommended by the vehicle manufacturer or the equivalent. They are currently disappearing hundreds of different models and are getting about 4 generic types of plugs for all motor.
The spark plug is a very useful to see the operation of the engine, as colors and acquires deposits similar to those in the combustion chamber mirror. Correct reading your expert eyes can deduct the mixture, detonation, and presence of oil and proper heat range of the spark plug.
It is a key to diagnosis in all synchronization. Electrodes that can be repaired (if not especially metal) with a flat condition for the spark to jump to the edges and the distance between them are recalibrated spent. Unless it is loose or broken pottery and loses compression, spark plug has no other problems.
When dirty excess oil (engine damaged), petrol (poorly tuned) or charcoal (fruit of the previous two) electrodes are isolated and not the spark. Although a passenger remedy is not correct to claim correct engine problems such as those cited by changing the heat range of the spark plug, which must always be the one who kicks the engine workshop manual. The special metal plugs do not increase engine power as evil but pray commercials are better conductors of electricity and less susceptible to fouling, especially in the cold start. The same goes for the multiple electrodes rise but ultimately not one spark and it seeks the best point, but does not improve performance.
Excessive electrode distance can also hinder or prevent spark jumping, so many recover with calibration.
Symptoms: Damaged or dirty spark plug is seen immediately by a lack of power (the work of the affected cylinder is lost) and the noise of engine failure is very easy to learn and detect.
Lifecycle: Spark plugs last 30,000 miles easily and more. If they are calibrated, you can extend your life once done service