How To Service Spark Plug

The air and fuel mixture in the engine ignited by the spark from the spark plugs. If not all of your spark plugs are firing properly, this may cause the vehicle to backfire or running rough. The engine may eventually fail to start if the problem isn’t corrected. Poor spark-plug performance because of carbon buildup or other residue will also reduce your vehicle power and its fuel efficiency.

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An engine tune-up typically includes replacing the spark plugs and spark-plug wires. Improved technology has done a lot to lengthen service intervals for newer cars. Whereas some older vehicles should be tuned every 30,000 miles, some newer ones can go as far as 100,000 before the first major tune-up. Even if you have a newer model, it’s a good idea to check your spark plugs about every 60,000 miles.

Replace the spark-plug wires too if you determine that your spark plugs need to be changed. To make sure you purchase the correct replacement plugs please check the owner’s manual. Use masking tape and a marker to number the old wires so it will be easier to install the replacements in the correct order. To prevent a mix-up, work on one spark plug and wire at a time.

Materials and tools needed:

Socket wrench, extender and spark-plug socket
Torque wrench
Feeler gauge
Masking tape
Dielectric grease
Antiseize lubricant

Firstly, disconnect the wire from the spark plug and leave the other end of the wire attached to the distributor cap. Disconnect by grasping the wire’s rubber boot and twisting it away gently.

Then remove the old spark plug, using a socket wrench, an extender and a spark-plug socket.

Prepare each new plug before installing it: Use a feeler gauge to “gap” the new plug. Check your owner’s manual or a service manual to determine the correct gap, then slide the appropriate-sized feeler between the electrodes. The feeler should slide out freely, with only a slight drag. If the electrode needs to be adjusted, use the adjuster on the end of the tool. Apply a small amount of antiseize lubricant to the threads on the new plugs to make sure they can be removed the next time the plugs need replacing.

Install the new plug, using the extender and the spark-plug socket. Take care not to cross threads. Use a torque wrench to tighten the plug to the proper specifications, as indicated by your owner’s manual.