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How to Change Your
Spark Plug |
How to Change Your Spark Plugs
What you will need:
3/8 drive Spark plug socket, extension and ratchet
New set of spark plugs
Spark plug gaping gauge
Rag or brush
Length of 5/16" vacuum line about 12" long
Why replace your spark plugs?
Spark plugs are one of the most important parts of your vehicle's
engine. Your spark plugs should be replaced every 2 years or 30,000
miles to maintain maximum fuel economy and peak engine performance.
This may vary depending on the make and model of your vehicle. Some
models will go as far as 100,000 miles before the plugs need
replacement. Replacing your spark plugs isn't that difficult but, be
sure to read all the instructions listed below.
Before you start:
Get all the tools you'll need and gap your spark plugs. The proper
spark plug gap can be found on the engine specifications decal under
the hood. Get the right plugs for your car. I always recommend using
the brand of plugs originally installed in your car from the
factory. For Ford products they are Motorcraft , General Motors
products use AC Delco and in Chrysler products they are Champion. In
Japanese cars I would use NGK and in German cars I would use Bosch.
Consult a parts guide to get the correct spark plugs. A cross
reference will not often get you the exact plug you need.
Okay, let's get to work.
Always change your spark plugs with the engine cold. Grabbing the
plug wire by the boot, carefully pull the spark plug wire from the
end of the spark plug. Do not pull the wire itself. If the boot
sticks, twist the boot left and right and pull the plug wire off. I
would recommend changing the plugs one at a time to avoid mixing up
the spark plug wires.
If you have it, use compressed air to blow any dirt away from the
spark plug area. Otherwise, clean off the old plug and the area
around it with a rag or small brush. This will help prevent any
foreign material from falling into the cylinder when the plug is
removed.
Remove the plug by turning it counterclockwise with a spark plug
socket and ratchet. Once you crack it loose, spin it out about three
or four turns. Then remove the socket and remove it completely by
hand. If you can't reach it, slip the 5/16" vacuum line over the
spark plug and turn it out with that.
If you haven't done so yet, gap the new plug with a spark plug gap
gauge (The proper gap can be found on the engine specifications
decal under the hood). Slip the correct thickness wire or feeler
between the inner and outer electrodes at the tip of the plug. A
flat gauge is good; the wire type is better. When the plugs are
properly gapped, the wire or feeler should slide between the
electrodes with a slight drag. If the gap is incorrect, gently bend
the outer electrode slightly until the correct gap is achieved. Make
sure that the outer electrode is centered directly over the inner
electrode. If it's not, align the two by gently bending the outer
electrode
Take a good look at the cylinder head threads. They should be in
good condition, clean, and free of dirt and debris. This new spark
plug should freely screw into the cylinder head by hand. Any binding
of the plug is an indication that there's a problem. Remove the plug
and inspect the threads.
Insert the plug into the spark plug hole by hand and turn it
clockwise until it's snug. I always attach a short piece of 5/16"
rubber hose to the top of the plug and use it as an extension to
install the new plugs
After installing the plug by hand as far as it will go, firmly
tighten it with a spark plug wrench or socket. It's a good idea to
use a torque wrench, if one is available, to ensure that the plug's
properly seated. Be very careful; do not over tighten the spark
plugs. Remember, you'll get an accurate torque reading only if the
spark plug and cylinder head threads are clean and dry.
Reattach the plug wire to the new plug. Use a twisting motion on the
boot until it's firmly seated on the top of the plug. You will feel
and hear a click as the wire clamps onto the spark plug.
Repeat these same steps for the other plugs. If you take your time
this is a fairly easy job and will probably take you about an hour,
depending on how many plugs your vehicle has. |
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