What You Need to
Know About . . . Spark Plugs
|What is this?
Spark plugs are little devices inside the cylinder that take
in high voltage electricity at one end and create a spark at
the other end. There, the spark ignites the gas and air
mixture, and the resulting combustion is what ultimately
powers the car. This service involves removing the old spark
plugs and replacing them with new ones.
Should I do this service when it¡¯s recommended?
Yes. Spark plugs wear out and need to be replaced at
Why do I have to do this?
|Tools needed to
replace spark plugs include a specialized socket, a
ratchet and an extension long enough to reach the
At the ¡°sparking¡± end of the spark plug is a built-in gap
between two or more little pieces of metal, called
¡°electrodes.¡± When the plug ¡°fires,¡± one or more sparks jump
that gap and a tiny bit of the metal is burned off. This
happens hundreds of times every minute. Over time, the gap
between the metal tips gets too big.
Also, your spark plugs can get fouled, but that would
indicate that you have a problem.
What happens if I don¡¯t do this?
Your engine will start to misfire and run poorly,
performance will suffer, efficiency will decrease and
emissions will dramatically increase. Your car may also be
difficult to start.
Can I do this myself?
It depends on where you rank on the Car Talk do-it-yourself
___ There are two kinds of screwdrivers?
___ I¡¯ve successfully hung pictures around the house.
___ I¡¯ve changed my own oil.
_X_ I¡¯ve fixed things on my car that involve removing more
than five bolts.
___ I¡¯ve built a working nuclear reactor out of wood.
Changing spark plugs is relatively easy, but it requires
specialized tools and some instruction your first time from
a mechanic or friend.
Is there any maintenance required
gauge/tool is used to measure the spark plug gap
and, if necessary, to bend the electrode to achieve
the correct specification.
We recommend removing the old spark plugs and reinstalling
new ones at least every 30,000 miles.
Many manufacturers have long-life, 60,000- or 90,000-mile
spark plugs. If you don¡¯t remove these spark plugs until
they¡¯re due to be changed, you might find it extremely
difficult or even impossible to remove them when the time
comes. You¡¯ll also want to examine the plugs if your car is
running poorly. A blackened plug, for example, can tell you
that the engine is running too rich.