Why should spark plugs be changed?

Answer 1

What is a spark plug? Basically it's a high voltage bridge for electricity. When the electricity crosses the "bridge" (which is actually a gap between two contact points) inside your engine, the spark it makes ignites the gas vapors, which makes the engine go putt putt. How long they can do this without being replaced depends on lots of things. The condition of your engine, the purity of the fuel you're using, even your driving habits can affect the life of the plugs. But hey, they're cheap, so replacing them every so often can't be a waste of money.

While you have your old plug in your hand, take a look at it. It should be a little dirty on the end, a little black with a little soot, the key phrase being "a little." If it's white or oily, this could indicate other problems so make a note of how they're looking. Also check to see if the porcelain insulator is cracked.

* A spark plug is what ignites the gasoline in an engine. The actual part that does the work is called the electrode. Electrodes tend to dull and wear out over time. In order to have a well maintained and efficient engine, spark plugs must be change according to the manufacture recommendations--- this can be from 30,000 miles to 100,000 miles *in some newer cars.